Devices, systems and methods for monitoring knee replacements

ABSTRACT

Knee replacement prosthesis are provided, comprising a plurality of sensors and at least one of a femoral component, a patellar prosthesis and a tibial component.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application No. 61/838,317 filed Jun. 23, 2013, whichapplication is incorporated herein by reference in its entirety.

BACKGROUND

1. Field of the Invention

The present invention relates generally to knee replacements, and morespecifically, to devices and methods for monitoring the performance oftotal and partial knee replacements

2. Description of the Related Art

Knee replacement is one of the most common reconstructive orthopedicsurgical procedures. It may be carried out when the patient losessufficient use of the knee, typically as a result of osteoarthritis,rheumatoid arthritis and other forms of arthritis (lupus, psoriatic andothers), a previous knee injury (knee ligament tears (anterior cruciate,posterior cruciate, medial collateral and/or lateral collateralligaments) and meniscus tears) and the sequellae of previousreconstructive surgery for the treatment for these conditions, articularcartilage injuries, joint dislocations, intra-articular fractures, andinfections. Typically, the surgery is indicated for the treatment ofextreme or constant joint pain, loss of range of motion, impairedambulation and/or the loss of function and impairment in the activitiesof normal daily living; usually being indicated when there is evidenceof significant loss or degeneration of the articular cartilage of all orparts of the knee.

The knee is generally divided into three “compartments”, medial (thejoint surface on the inside of the knee), lateral (the joint surface onoutside of the knee), and patellofemoral (the joint between the kneecapand the thighbone or femur). Knee replacement can take a variety ofdifferent forms, depending on the degree of injury and/or the extent ofthe disease. In total knee replacement (TKR), both surfaces of the kneejoint are replaced (i.e., the femoral articular surface and the tibialarticular surface of the joint are replaced by a prosthesis); thepatellar (kneecap) surface may/or may not be replaced depending on thedegree of damage to the patella. In a partial or unicompartmental kneereplacement, only one or two of the medial, lateral or patellofemoralportions of the joint are replaced (medial compartment replacement isthe most common).

The various components of a TKR typically include femoral implant and atibial implant (with or without replacing the surface of the patella).The femoral component consists of a rounded femoral condyle (oftenmetal, but can be ceramic), the tibial component consists of a flatmetal shell (with or without a stem that extends into the medullarycanal of the tibia) that attaches to the tibia with an inner polymeric(often polyethylene, but ceramic and metal can be used) surface liner,and the patellar component (if present) consists of a polymeric “button”cemented to the posterior surface of the patella. Currently, the variouscomponents of a TKR can be made from a variety of different materials,including for example, polyethylene, ultrahigh molecular weightpolyethylene, ceramic, surgical-grade stainless steel, cobalt chromium,titanium, and various ceramic materials. Within certain devices, thefemoral implant (typically made of a metal such as stainless steel,titanium, or cobalt chromium) and the metal portion of the tibialcomponent (typically also made of a metal such as stainless steel,titanium, or cobalt chromium) can be designed with a surface coating toencourage incorporation of the implant within the bone of the femur andthe tibia. The prosthesis may or may not be held in place with the useof bone cement (PMMA—polymethylmethacrylate). Representative examples ofthe various components of a knee replacement are described in U.S. Pat.Nos. 5,413,604, 5,906,643, 6,019,794 and 7,922,771.

FIG. 1 shows a total knee joint of a type known in the art, as well as aunicompartmental (medial compartment) knee replacement. FIG. 2illustrates the components and materials of a typical artificial joint(10), including a metallic tibial plate (5) and tibial stem (2) (presentin this Figure, although some tibial plate components do not havestems), a polyethylene articulating surface (7), cement used to hold thevarious components in place (4), patellar “button” prosthesis (8), andthe femoral knee component 9. FIG. 3 depicts another typical TKR, with afemoral component, a tibial plate and a patellar button which may beattached with screws and/or cement to the underlying bone (as opposed toa stemmed tibial plate).

Unfortunately, when a total knee is inserted, various complications mayarise intra-operatively, in the post-operative period and over time. Forexample, intra-operatively, the surgeon may wish to confirm correctanatomical alignment of the prosthesis and/or any motion between theprosthesis and the surrounding bone so that adjustments can be madeduring the procedure. Post-operatively, the patient may experienceinflammation and pain if there is slight movement, partial (subluxation)or full dislocation of any of the components of the knee prosthesis.Longer term, there may be progressive wear between the femoral surfaceand the tibial surface, which leads to improper operation of the kneejoint. Depending on the types of materials used for the tibial surfaceand the femoral surface, prolonged wear can result in the generation ofsmall debris particles which lead to inflammation and bone erosionsurrounding the implant. A related common complication occurs when, overa period of time (for example 8-12 years), bone loss occurs in thetissues surrounding the implant (due to a process known as osteolysis)that leads to loosening and ultimately failure of the prosthesis. All ofthe above acute and chronic complications may degrade the performance ofthe knee, result in difficulty in movement and ambulation, and may causepain and inflammation for the patient.

As mentioned, one of the most common and serious complications of TKR iserosion of the bone around the implant (osteolysis) which may be causedby material debris (metal, ceramic, and/or polyurethane fragments)generated by friction, and causing inflammation and bone loss. Otherpotential causes of inflammation and osteolysis are implant vibrationand motion, improper patient usage/activities, improper alignment(including improper tracking of the patella), subclinical dislocation(subluxation) of the tibial-femoral joint and the patellar-femoraljoint, mechanical wear and tear, material failure or breakage, looseningof the bond between the bone and the cement, lack of biocompatibilitybetween the implant materials and the surrounding bone, metal allergy,and lack of biocompatibility between the bone cement and the surroundingbone. The ability to detect these changes early and institute correctiveor preventative measures would be of great utility in the management ofTKR patients. Additional complications that could benefit from earlydetection and intervention include infection, bone fracture, implantmicrofracture, nerve impingement, deep vein thrombosis, loss of motion,and instability.

Currently, post-operative, in-hospital monitoring of knee replacementsurgery patients is conducted through personal visits by the hospitalstaff and medical team, physical examination of the patient, medicalmonitoring (vital signs, etc.), evaluation of knee range of motion(ROM), physiotherapy (including early mobilization and activity), anddiagnostic imaging studies and blood work as required. Once the patientis discharged from hospital, prosthesis performance and patientsatisfaction is checked during periodic doctor's office visits where athorough history, physical exam and supplemental imaging and diagnosticstudies are used to monitor patient progress and identify thedevelopment of any potential complications. During such visits, thesurgeon typically evaluates the range of motion of the knee, attempts toidentify any pain that occurs during certain motions or actions, andquestions the patient to determine activity levels, daily functioning,pain control, and rehabilitation progress.

Unfortunately, most of the patient's recuperative period occurs betweenhospital and/or office visits. It can, therefore, be very difficult toaccurately measure and follow full joint range of motion (ROM can changedepending on pain control, degree of anti-inflammatory medication, timeof day, recent activities, and/or how the patient is feeling at the timeof the examination), “real life” prosthesis performance, patientactivity levels, exercise tolerance, and the effectiveness ofrehabilitation efforts (physiotherapy, medications, etc.) from the dayof surgery through to full recovery. For much of this information, thephysician is dependent upon patient self-reporting or third partyobservation to obtain insight into post-operative treatmenteffectiveness and recovery and rehabilitation progress; in many casesthis is further complicated by a patient who is uncertain what to lookfor, has no knowledge of what “normal/expected” post-operative recoveryshould be, is non-compliant, or is unable to effectively communicatetheir symptoms. Furthermore, identifying and tracking complications (inand out of hospital) prior to them becoming symptomatic, arising betweendoctor visits, or those whose presence is difficult for the patient(and/or the physician) to detect would also provide beneficial,additional information to the management of TKR and partial kneereplacement patients. Currently, in all instances, neither the physiciannor the patient has access to the type of “real time,” continuous,objective, prosthesis performance measurements that they might otherwiselike to have.

The present invention discloses novel total and partial kneereplacements which overcome many of the difficulties of previous kneeprostheses, methods for constructing and monitoring these novel kneereplacements, and further provides other related advantages.

SUMMARY

Briefly stated, full and partial knee prostheses are provided with anumber of sensors to monitor the integrity and efficaciousness of theartificial knee joint within the patient. The sensors may be positionedon the outer surface of the prosthetic knee, on the inner surfaces ofthe prosthetic knee, within the prosthetic material (stainless steel,titanium, cobalt chromium, polyurethane, high molecular weightpolyurethane, ceramics, etc.) itself, between the various componentsthat comprise the prosthetic knee, the screws and/or fastening hardware(if present) used to secure the prosthesis in place, within the bonecement (e.g., PMMA, or PMMA and MMA copolymer blends) used to secure theknee (if present), and/or within the tissues surrounding the prosthesis.Within certain embodiments, the sensors are of the type that are passiveand thus do not require their own power supply.

Within one aspect of the invention, assemblies are provided forpositioning and placement within a patient an implant comprising a totalor partial knee prosthesis; and one or more sensors positioned on, in,or around the prosthesis, and/or within the bone cement and/or bonescrews or anchors utilized to attach the prosthesis. Within otheraspects of the invention, medical devices are provided comprising atleast one of: a tibial component, patellar prosthesis, or femoralcomponent, and one or more sensors. For purpose of clarity, the one ormore sensors may be purposely placed at specific locations on the kneereplacement prosthesis, medical device, and/or bone screw or anchor,and/or randomly dispersed across, upon and within the knee replacementprosthesis, medical device, bone screw or anchor, and bone cement.Hence, use of the terms or phrases “are placed”, “appear” or “utilized”should not be deemed to require specific placement, unless a specificplacement is required.

Within various embodiments the sensor can be positioned on an outersurface of the prosthetic knee, on an inner surface of the prostheticknee, within the materials used to construct the prosthetic knee,between the various components that make up the prosthetic knee, thescrews and/or fastening hardware (if present) used to secure theprosthesis in place, on or in the bone cement used to secure theprosthetic knee, on or in the tissues surrounding the prosthetic knee(typically bone or bone marrow, but also muscle, ligament, tendon, jointcapsule and/or synovial compartment), or any combination of these.Representative examples of sensors suitable for use within the presentinvention include accelerometers (acceleration, tilt, vibration, shockand rotation sensors), pressure sensors, contact sensors, positionsensors, chemical microsensors, tissue metabolic sensors, mechanicalstress sensors and temperature sensors. Within particularly preferredembodiments the sensor is a wireless sensor, or a sensor connected to awireless microprocessor.

Within further embodiments a plurality of the aforementioned sensors arepositioned on, within, or around (bone cement, bone screws or tissue)the prosthetic knee, and within preferred embodiments, the prostheticknee can contain more than one type of sensor (e.g., one or more of, orany combination of the following: acceleration sensors, tilt sensors,vibration sensors, shock sensors, rotation sensors, pressure sensors,contact sensors, position sensors, chemical microsensors, tissuemetabolic sensors, and mechanical stress sensors).

According to various embodiments, sensors are placed at differentlocations in a replacement knee joint in order to monitor the operation,movement, medical imaging (both prosthesis and surrounding tissues),function, wear, performance, potential side effects, medical status ofthe patient and the medical status of the artificial knee and itsinterface with the live tissue of the patient. Live, continuous, insitu, monitoring of patient activity, patient function, prosthesisactivity, prosthesis function, prosthesis performance, prosthesis andjoint alignment, patellar tracking, prosthesis and joint forces andmechanical stresses, prosthesis and surrounding tissue anatomy(imaging), mechanical and physical integrity of the prosthesis, patellartracking and potential side effects is provided. In addition,information is available on many aspects of the knee replacementprosthesis and its interaction with the patient's own body tissues,including clinically important measurements not currently availablethrough physical examination, medical imaging and diagnostic medicalstudies.

According to one embodiment, the sensors provide evaluation data on therange of motion (ROM) of the knee. Currently, ROM is usually measuredclinically by the physician passively moving the knee joint through afull range of motion during physical examination and recording theresults (degrees of flexion, extension, anterior/posterior stability andmedial/lateral stability; see, e.g., FIG. 4). Motion sensors andaccelerometers can be used to accurately determine the full ROM of theprosthetic knee joint both during physical examination and during normaldaily activities between visits. Similarly, motion sensors andaccelerometers can be used to accurately measure any anterior/posterioror medial/lateral instability (including full, partial or subclinicaldislocation) of the prosthetic knee joint both during physicalexamination and during normal daily activities between visits.Additionally, motion sensors and accelerometers can be used toaccurately measure any improper tracking of the patella and/or patellarinstability (including full, partial or subclinical subluxation) duringphysical examination and during normal daily activities between visits.

According to one embodiment, contact sensors are provided between theprosthesis and the surrounding bone, between the screws and/or fasteninghardware (if present) and the surrounding bone, between the prosthesisand the surrounding bone cement (if present), and/or between the bonecement (if present) and the surrounding bone in order to measure boneerosion and loosening around the implant. In other embodiments,vibration sensors are provided to detect the vibration between theprosthesis and the surrounding bone, between the screws and/or fasteninghardware (if present) and the surrounding bone, between the prosthesisand the surrounding bone cement, between the bone cement and thesurrounding bone as an early indicator of motion and loosening. In otherembodiments, strain gauges are provided to detect the strain between theprosthesis and the surrounding bone, between the screws and/or fasteninghardware (if present) and the surrounding bone, between the prosthesisand the surrounding bone cement, between the bone cement and thesurrounding bone, and also the strain which is exerted on the variousportions of the prosthesis. Sudden increases in strain may indicate thattoo much stress is being placed on the replacement prosthesis, which mayincrease damage to the body. For example, a gradual, long-term decreasein strain may cause bone reabsorption around the implant, leading toloosening of the prosthesis or fractures in the bone surrounding theprosthesis, while a gradual, long-term increase in strain may lead tomicrofractures of the prosthesis materials themselves.

According to other embodiments, accelerometers are provided which detectvibration, shock, tilt and rotation. According to other embodiments,sensors for measuring surface wear, such as contact or pressure sensors,may be embedded at different depths within the femoral articularsurface, the tibial articular surface, and/or the patellar articularsurface in order to monitor articular surface erosion. In otherembodiments, position sensors, as well as other types of sensors, areprovided which indicate the range of motion and monitor for partial (orcomplete) femoral-tibial knee dislocation or subluxation in actual useover a period of time, improper tracking of the patella and/orsubluxation of the patellar-femoral joint, or movement between theinterconnected components of the prosthesis (and the anchoring hardware)itself.

Within further embodiments, the artificial knee (total or partial) cancontain sensors at specified densities in specific locations. Forexample, the artificial knee can have a density of sensors of greaterthan one, two, three, four, five, six, seven, eight, nine, or tensensors (e.g., acceleration sensors, tilt sensors, vibration sensors,shock sensors, rotation sensors, pressure sensors, contact sensors,position sensors, chemical microsensors, tissue metabolic sensors, andmechanical stress sensors, or any combination of these) per squarecentimeter of the device. Within other embodiments, the artificial knee(total or partial) can have a density of sensors of greater than one,two, three, four, five, six, seven, eight, nine, or ten sensors (e.g.,acceleration sensors, tilt sensors, vibration sensors, shock sensors,rotation sensors, pressure sensors, contact sensors, position sensors,chemical microsensors, tissue metabolic sensors, and mechanical stresssensors, or any combination of these) per cubic centimeter of thedevice. Within related embodiments, the sensors (e.g., accelerationsensors, tilt sensors, vibration sensors, shock sensors, rotationsensors, pressure sensors, contact sensors, position sensors, chemicalmicrosensors, tissue metabolic sensors, and mechanical stress sensors)can be positioned at particular locations on, within, or around theartificial knee, including for example, the femoral component (medial,lateral or both), the tibial plate, the tibial stem (if present), thetibial lining, the prosthetic patellar lining, within portions of thedevice which are to be connected (e.g., the connecting segments of thetibial cup and the tibial lining), the screws and/or fastening hardware(if present) used to secure the prosthesis in place, and around theartificial knee (on or in the bone cement used to secure the prostheticknee, on or in the tissues surrounding the prosthetic knee—typicallybone or bone marrow, but also muscle, ligament, tendon, joint capsuleand/or synovial compartment).

Within certain embodiments of the invention, the total or partial kneeprosthesis is provided with a specific unique identifying number, andwithin further embodiments, each of the sensors on, in or around theprosthetic knee each have either a specific unique identificationnumber, or a group identification number (e.g., an identification numberthat identifies the sensor as an acceleration sensor, a tilt sensor, avibration sensor, a shock sensor, a rotation sensor, a pressure sensor,a contact sensor, a position sensor, a chemical microsensor, a tissuemetabolic sensor, or a mechanical stress sensor). Within yet furtherembodiments, the specific unique identification number or groupidentification number is specifically associated with a position on, inor around the prosthetic knee.

Within other aspects of the invention methods are provided formonitoring an implanted total or partial knee prosthesis comprising thesteps of transmitting a wireless electrical signal from a locationoutside the body to a location inside the body; receiving the signal ata sensor positioned on, in or around an artificial knee located insidethe body; powering the sensor using the received signal; sensing data atthe sensor; and outputting the sensed data from the sensor to areceiving unit located outside of the body.

Within other aspects of the invention methods are provided for imaging aknee replacement or medical device as provided herein, comprising thesteps of (a) detecting the location of one or more sensors in a kneereplacement or medical device; and (b) visually displaying the locationof said one or more sensors, such that an image of the knee replacementor medical device is created. Within various embodiments, the step ofdetecting may be done over time, and the visual display may thus showpositional movement over time. Within certain embodiments the imagewhich is displayed is a two or three-dimensional image. Within preferredembodiments the various images may be collected and displayed in atime-sequence (e.g., as a moving image or ‘movie-like’ image).

The imaging techniques provided herein may be utilized for a widevariety of purposes. For example, within one aspect, the imagingtechniques may be utilized during a surgical procedure in order toensure proper placement and working of the knee replacement or medicaldevice. Within other embodiment, the imaging techniques may be utilizedpost-operatively in order to examine the knee replacement or medicaldevice, and/or to compare operation and/or movement of the device overtime.

The integrity of the partial or total knee prosthesis can be wirelesslyinterrogated and the results reported on a regular basis. This permitsthe health of the patient to be checked on a regular basis or at anytime as desired by the patient and/or physician. Furthermore, theprosthesis can be wirelessly interrogated when signaled by the patientto do so (via an external signaling/triggering device) as part of “eventrecording”—i.e. when the patient experiences a particular event (e.g.pain, injury, instability, etc.) she/he signals/triggers the device toobtain a simultaneous reading in order to allow the comparison ofsubjective/symptomatic data to objective/sensor data. Matching eventrecording data with sensor data can be used as part of an effort tobetter understand the underlying cause or specific triggers of apatient's particular symptoms. Hence, within various embodiments of theinvention methods are provided for detecting and/or recording an eventin a subject with one of the total or partial knee replacements providedherein, comprising the interrogating at a desired point in time Hence,within one aspect of the invention methods are provided for detectingand/or recording an event in a subject with a knee replacement ormedical device as provided herein, comprising the step of interrogatingat a desired point in time the activity of one or more sensors withinthe knee replacement or medical device, and recording said activity.Within various embodiments, they may be accomplished by the subjectand/or by a health care professional. Within related embodiments, thestep of recording may be performed with one or more wired devices, or,wireless devices that can be carried, or worn (e.g., a cellphone, watch,wristband, and/or glasses). Within further embodiments, the worn devices(e.g. cellphone, watch, wristband and/or glasses may have sufficientprocessing power and memory to be able to carry out further datacollection and analysis.

Within further embodiments, each of the sensors contains asignal-receiving circuit and a signal output circuit. Thesignal-receiving circuit receives an interrogation signal that includesboth power and data collection request components. Using the power fromthe interrogation signal, the sensor powers up the parts of thecircuitry needed to conduct the sensing, carries out the sensing, andthen outputs the data to the interrogation module. The interrogationmodule acts under control of a control unit which contains theappropriate I/O circuitry, memory, a controller in the form of amicroprocessor, and other circuitry in order to drive the interrogationmodule. Within yet other embodiments the sensor (e.g., an accelerationsensor, a tilt sensor, a vibration sensor, a shock sensor, a rotationsensor, a pressure sensor, a contact sensor, a position sensor, achemical microsensor, a tissue metabolic sensor, or a mechanical stresssensor) are constructed such that they may readily be incorporated intoor otherwise mechanically attached to the knee prosthesis (e.g., by wayof a an opening or other appendage that provides permanent attachment ofthe sensor to the knee prosthesis) and/or readily incorporated into thebone cement or the tissues that surround the knee prosthesis.

Within yet other aspects of the invention methods devices are providedsuitable for transmitting a wireless electrical signal from a locationoutside the body to a location inside the body; receiving the signal atone of the aforementioned sensors positioned on, in or around aprosthetic knee located inside the body; powering the sensor using thereceived signal; sensing data at the sensor; and outputting the senseddata from the sensor to a receiving unit located outside of the body.Within certain embodiments the receiving unit can provide an analysis ofthe signal provided by the sensor.

The data collected by the sensors can be stored in a memory locatedwithin the femoral component, the tibial plate and/or the tibial stem.During a visit to the physician, the data can be downloaded via awireless sensor, and the doctor is able to obtain data representative ofreal-time performance of the prosthesis.

The advantages obtained include more accurate monitoring of theprosthesis and permitting medical reporting of accurate, in situ, datathat will contribute to the health of the patient. The details of one ormore embodiments are set forth in the description below. Other features,objects and advantages will be apparent from the description, thedrawings, and the claims. In addition, the disclosures of all patentsand patent applications referenced herein are incorporated by referencein their entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a total knee replacement, and aunicompartmental knee replacement.

FIG. 2 is an exploded view which illustrates various components of atotal knee replacement.

FIG. 3 illustrates the components of another total knee replacement.

FIG. 4 illustrates a representative range of motion (ROM) for a subjectwith a total knee replacement.

FIG. 5 illustrates a TKR with various contact sensors.

FIG. 6 illustrates a TKR with various strain gauges.

FIG. 7 illustrates a TKR with various accelerometers.

FIG. 8 illustrates a TKR with various positional sensors.

FIG. 9 illustrates a TKR with sensors placed to detect articular wear.

FIG. 10 illustrates an information and communication technology systemembodiment arranged to process sensor data.

FIG. 11 is a block diagram of a sensor, interrogation module, and acontrol unit according to one embodiment of the invention.

FIG. 12 is a schematic illustration of one or more sensors positioned ona knee replacement within a subject which is being probed for data andoutputting data, according to one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Briefly stated the present invention provides a variety of kneereplacements that can be utilized to monitor the integrity andefficaciousness of the device. Prior to setting forth the inventionhowever, it may be helpful to an understanding thereof to first setforth definitions of certain terms that are used hereinafter.

“Knee replacement” or “knee prosthesis” as that term is utilized herein,may take a variety of different forms and may involve replacement of all(total knee replacement) or portions (partial knee replacement) of thepatient's knee joint with synthetic materials. In total knee replacement(TKR), both the femoral side and the tibial side are replaced. In apartial or unicompartmental knee replacement, only one or two portions(surfaces—tibial or femoral; or compartments—medial, lateral orpatellar) of the knee are replaced.

The various components of a TKR can typically include a femoral implant,a patellar implant, and a tibial implant (which can be composed of atibial plate—with or without a stem—and a tibial liner). Currently, thevarious components can be made from a variety of different materials,including for example, polyethylene, ultrahigh molecular weightpolyethylene, ceramic, surgical-grade stainless steel, cobalt chromium,titanium, and various ceramic materials. Within certain devices, thefemoral implant (typically made of a metal such as stainless steel,titanium, or cobalt chromium) can be designed with a bone surfacecoating to encourage incorporation of the implant within the femur andthe tibial plate (and stem) can also have a surface coating to encourageincorporation into the tibia. Representative examples of the variouscomponents of a knee replacement are described in U.S. Pat. Nos.5,413,604, 5,906,643, 6,019,794 and 7,922,771.

“Bone Cement” refers to a material that can be administered between theprosthetic hardware and the surrounding bone and hardens in place whencooled (or otherwise activated); it is an agent used to secure one ormore of the components (the prosthetic femur surface, the tibialplate/stem, the patellar “button”) of the prosthesis to the appropriatebony tissue (femur, tibia, tibial medulla, patella). Bone cement isoften composed of PMMA (polymethylmethacrylate) or PMMA and MMAcopolymer blends. It should be noted that bone screws and/or othermetallic (or polymeric) securing devices can also be used to assist inanchoring the prosthetic components to the surrounding bony tissues.

The present invention provides knee prosthesis (which may include a fullor a partial implant), medical devices (e.g., a portion of a kneeimplant, and/or components or materials which are useful in the processof implanting the device), and kits (e.g., a knee prosthesis, medicaldevice, and additional necessary materials such as bone cement and anyassociated delivery devices), all of which have sensors as described infurther detail below. The knee prosthesis, medical devices and kits asprovided herein (including related materials such as bone cement) arepreferably sterile, non-pyrogenic, and/or suitable for use and/orimplantation into humans. However, within certain embodiments of theinvention the knee prostheses, medical devices and/or kits can be madein a non-sterilized environment (or even customized to an individualsubject), and sterilized at a later point in time.

“Sensor” refers to a device that can be utilized to measure one or moredifferent aspects of a body, of a knee prosthesis, medical device or kitinserted within a body, and/or the integrity, impact, efficaciousness oreffect of the knee prosthesis, medical device or kit inserted within abody. Representative examples of sensors suitable for use within thepresent invention include, for example, fluid pressure sensors, contactsensors, position sensors, pulse pressure sensors, liquid (e.g., blood)volume sensors, liquid (e.g., blood) flow sensors, chemistry sensors(e.g., for blood and/or other fluids), metabolic sensors (e.g., forblood and/or other fluids), accelerometers, mechanical stress sensorsand temperature sensors. Within certain embodiments the sensor can be awireless sensor, or, within other embodiments, a sensor connected to awireless microprocessor. Within further embodiments one or more(including all) of the sensors can have a Unique Sensor Identificationnumber (“USI”) which specifically identifies the sensor.

A wide variety of sensors (also referred to as MicroelectromechanicalSystems or “MEMS”, or Nanoelectromechanical Systems or “NEMS”, andBioMEMS or BioNEMS, see generally https://en.wikipedia.org/wiki/MEMS)can be utilized within the present invention. Representative patents andpatent applications include U.S. Pat. Nos. 7,383,071 and 8,634,928, andU.S. Publication Nos. 2010/0285082, and 2013/0215979. Representativepublications include “Introduction to BioMEMS” by Albert Foch, CRCPress, 2013; “From MEMS to Bio-MEMS and Bio-NEMS: ManufacturingTechniques and Applications by Marc J. Madou, CRC Press 2011; “Bio-MEMS:Science and Engineering Perspectives, by Simona Badilescu, CRC Press2011; “Fundamentals of BioMEMS and Medical Microdevices” by Steven S.Saliterman, SPIE—The International Society of Optical Engineering, 2006;“Bio-MEMS: Technologies and Applications”, edited by Wanjun Wang andSteven A. Soper, CRC Press, 2012; and “Inertial MEMS: Principles andPractice” by Volker Kempe, Cambridge University Press, 2011; Polla, D.L., et al., “Microdevices in Medicine,” Ann. Rev. Biomed. Eng. 2000,02:551-576; Yun, K. S., et al., “A Surface-Tension Driven Micropump forLow-voltage and Low-Power Operations,” J. Microelectromechanical Sys.,11:5, October 2002, 454-461; Yeh, R., et al., “Single Mask, Large Force,and Large Displacement Electrostatic Linear Inchworm Motors,” J.Microelectromechanical Sys., 11:4, August 2002, 330-336; and Loh, N. C.,et al., “Sub-10 cm³ Interferometric Accelerometer with Nano-gResolution,” J. Microelectromechanical Sys., 11:3, June 2002, 182-187;all of the above of which are incorporated by reference in theirentirety.

Within various embodiments of the invention the sensors described hereinmay be placed at a variety of locations and in a variety ofconfigurations, including on the inside, within, and/or outer surface(or surfaces) of the knee prosthesis, medical device or kit, as well asbetween the knee prosthesis, medical device or kit and any device itmight carry (e.g., a delivery or installation device). As will bereadily evident given the disclosure provided herein, the sensors may beplaced at multiple locations (i.e., inside, within and on the outersurface) of the knee prosthesis, medical device or kit at the same time.Within certain embodiments the knee prosthesis, medical device or kit,associated medical device (e.g., delivery instrument) or kit comprisessensors at a density of greater than 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 orgreater than 10 sensors per square centimeter. Within other aspects theknee prosthesis, medical device or kit, associated medical device (e.g.,delivery instrument) or kit comprises sensors at a density of greaterthan 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or greater than 10 sensors per cubiccentimeter. Within either of these embodiments there can be less than50, 75, 100, or 100 sensors per square centimeter, or per cubiccentimeter. Within various embodiments the at least one or more of thesensors may be placed randomly, or at one or more specific locationswithin the catheter, medical device, or kit as described herein.

In various embodiments, the sensors may be placed within specificlocations and/or randomly throughout the knee prosthesis, medical deviceor kit, associated medical device (e.g., delivery instrument) or kit. Inaddition, the sensors may be placed in specific patterns (e.g., they maybe arranged in the pattern of an X, as oval or concentric rings aroundthe knee prosthesis, medical device or kit, associated medical device(e.g., delivery instrument) or kit.

Representative Embodiments of Knee Prosthesis, Medical Devices and Kits

In order to further understand the various aspects of the inventionprovided herein, the following sections are provided below: A. KneeProsthesis, Medical Devices and Kits and their Use; B. Use of KneeProsthesis, Medical Devices and Kits to Deliver Therapeutic Agent(s); C.Use of a Knee Prosthesis, Medical Device or Kit having Sensors toMeasure Degradation or Wearing of an Implant; D. Methods for MonitoringInfection in Knee Prosthesis, Medical Devices and Kits; E. Further Usesof Sensor-containing Knee Prosthesis, Medical Devices and Kits inHealthcare; F. Generation of Power from Knee Prosthesis, Medical Devicesand Kits; G. Medical Imaging and Self-Diagnosis of Assemblies ComprisingKnee Prosthesis, Medical Devices and Kits, Predictive Analysis andPredictive Maintenance; H. Methods of Monitoring Assemblies ComprisingKnee Prosthesis, Medical Devices and Kits; and I. Collection,Transmission, Analysis, and Distribution of Data from AssembliesComprising Knee Prosthesis, Medical Devices and Kits.

A. Knee Prosthesis, Medical Devices and Kits and their Use

Knee replacement is carried out when the patient loses sufficient use ofthe knee so as to result in disability, loss of movement and function,impaired ambulation, and/or continuous joint pain and discomfort. Commoncauses of impaired knee function leading to total or partial kneereplacement include various types of arthritis (such as rheumatoidarthritis or osteoarthritis, and trauma (for example, previous kneeligament injuries or cartilage/meniscus tears). In most patients, theoperation is successful in improving ambulation, restoring normal dailyfunction and reducing pain; as a result, it is a very common orthopedicprocedure in the Western World.

FIGS. 5, 6, 7, 8 and 9 illustrate several prosthesis 10 in the form of atotal knee replacement having one or more sensors positioned in or onthe prosthesis in order to monitor, in situ, the real-time operation ofthe prosthesis, levels of patient function and activity, and theprosthesis performance acutely and over time. A variety of these sensorswill now be described according to various embodiments.

In one embodiment shown in FIG. 5, one or more contact sensors 22 areprovided throughout the implant, including contact sensors 22Adistributed on and within the femoral condyle prosthesis-bone interface,contact sensors 22B distributed on and within the tibial bone—metalplate (and stem if present) interface, and contact sensors 22Cdistributed on within the patellar prosthesis (patellar“button”)—patellar bone interface. In some embodiments, the contactsensors are on the prosthetic components themselves (tibial, femur andpatellar segments), while in others the contact sensors are containedon/within the bone cement (if present) used to secure the prosthesis tothe surrounding bone, and in still other embodiments the contact sensorsare contained on/within both the prosthetic components and the bonecement (PMMA).

In various embodiments, these sensors may be positioned in a variety ofdifferent patterns on the prosthetic components based on their contactlocations with respect to the surrounding bone (femur, tibia and/orpatella) and/or the surrounding bone cement (if present). For example,they may be arranged in the pattern of an X, as oval or concentric ringsaround the various components or in various other patterns, in order tocollect accurate data on the physical contact between the tibialcomponent and the tibia and/or surrounding bone cement (if present), thefemoral component and the femur and/or surrounding bone cement (ifpresent), and the patellar component and the patella and/or surroundingbone cement (if present). Contact sensors can also be dispersedwithin/arranged within the bone cement (if present) so as to collectdata on the physical contact between the bone cement and the componentsof the prosthesis (femoral, tibial and patellar) and/or between the bonecement and the bone (femur, tibia, patella) itself.

Within various embodiments of the invention contact sensors are placedon the tibial component, femoral component, and/or patellar componentsof the knee prosthesis, and/or in the bone cement securing thecomponents of the prosthesis to the surrounding bone, at a density ofgreater than one, two, three, four, five, six, seven, eight, nine, orten sensors per square centimeter, or, per cubic centimeter of theprosthetic device component and/or per cubic centimeter of bone cement.

Within other aspects of the invention methods are provided for imaging aknee replacement or medical device as provided herein, comprising thesteps of (a) detecting the location of one or more sensors in a kneereplacement or medical device; and (b) visually displaying the locationof said one or more sensors, such that an image of the knee replacementor medical device is created. Within various embodiments, the step ofdetecting may be done over time, and the visual display may thus showpositional movement over time. Within certain preferred embodiments theimage which is displayed is a three-dimensional image.

The imaging techniques provided herein may be utilized for a widevariety of purposes. For example, within one aspect, the imagingtechniques may be utilized during a surgical procedure in order toensure proper placement and working of the knee replacement or medicaldevice. Within other embodiment, the imaging techniques may be utilizedpost-operatively in order to examine the knee replacement or medicaldevice, and/or to compare operation and/or movement of the device overtime.

Within one embodiment the contact sensors 22 (22A, 22B, 22C) can detectloosening of the prosthesis 10 and its connection to the surroundingcement (if present) and/or bone. For example, the contact sensorslocated on/in the tibial component and/or on/in the bone cement aroundthe tibial component (22B), can detect loosening of the tibial componentwithin the tibia; this can be detected acutely during surgery and alertthe surgeon that some intra-operative adjustment is required.Progressive loosening of the tibial component within the tibia over time(as compared to post-operative levels) is a common complication thatoccurs when bone loss takes place (e.g., due to a process known asosteolysis); this too can be detected by the contact sensors on/in thetibial component and/or on/in the surrounding bone cement. Furthermore,contact sensors located between segments of the tibial component (e.g.between the tibial plate and the tibial liner) can detect abnormalmovement, loosening, or wear between component segments; these sensorscan be “matching” (i.e. “paired” between adjacent components) so as toalso allow accurate fitting during (and after) surgical placement.

Thus, in the embodiment of FIG. 5, a variety of contact sensors areprovided in order to monitor contact between the tibia and the tibialcomponent, between the femur and the femoral component, between thepatella and the patellar component, between the complimentary segmentsof the individual prosthetic components, and between the variousarticular surfaces present (medial and lateral tibial-femoral joint; thepatellar-femoral joint) of a multi-compartmental or uni-compartmentalprosthetic knee joint. Specifically, full or partial dislocation(subluxation) of the femoral prosthetic joint surface from the naturalor synthetic tibial joint surface (medial, lateral or both) of aprosthetic knee is a common complication of knee replacement, oftenoccurring shortly after surgery (particularly during the post-operativerecovery period when the surrounding muscles and ligaments are stillhealing from surgery). Contact sensors on the femoral componentarticular surface and/or tibial component articular surface can alertthe patient and the healthcare provider if joint dislocation orsubluxation has occurred. This is of particular value in the detectionof subclinical partial or incomplete dislocation (subluxation) of theknee joint which may not be readily evident to the patient or thephysician; this is of greatest concern during early mobilization andpost-operative rehabilitation efforts. Additionally, contact sensors onthe various knee components can determine of the joint is functioningand aligning (tracking) correctly during movement and activity. This isparticularly true with respect to the movement of the knee cap, asaccurate patellar tracking can be difficult to accurately measureclinically; accurate measurement of patellar tracking, bothintra-operatively and post-operatively, would be beneficial.

In another embodiment shown in FIG. 6, one or more strain gauges (orsensors) 26 are provided throughout the implant, including strain gauges26A distributed on and within the femoral condyle prosthesis-boneinterface, strain gauges 26B distributed on and within the tibialbone—metal plate (and stem if present) interface, and strain gauges 26Cdistributed on within the patellar prosthesis (patellar“button”)—patellar bone interface. In some embodiments, the straingauges are on the prosthetic components themselves (tibial, femur andpatellar segments), while in others the strain gauges are containedon/within the bone cement (if present) used to secure the prosthesis tothe surrounding bone, and in still other embodiments the strain gaugesare contained on/within both the prosthetic components and the bonecement (PMMA).

In various embodiments, these strain gauges may be positioned in avariety of different patterns on the prosthetic components based ontheir contact locations with respect to the surrounding bone (femur,tibia and/or patella) and/or the surrounding bone cement (if present).For example, they may be arranged in the pattern of an X, as oval orconcentric rings around the various components or in various otherpatterns, in order to collect accurate data on the physical strainexperienced by the prosthetic components, the surrounding bone cement(if present), and the surrounding bone (femur, tibia, patella) tissue.

Within various embodiments of the invention strain sensors are placed onthe tibial component, femoral component, patellar prosthesis, and/or inthe bone cement at a density of greater than one, two, three, four,five, six, seven, eight, nine, or ten sensors per square centimeter ofthe prosthetic components, or, per cubic centimeter of PMMA bone cement.

The strain gauges 26 provide a different data point than the contactsensors 22. The contact sensors 22 merely specify whether there iscurrent contact between adjacent structures and thus provide a goodindication of whether there is abutting contact between two surfaces.However, they do not provide an indication of the physical strain thatis present in either the prosthetic surfaces or the surrounding bone; onthe other hand, the strain sensors 26 output data is indicative of themechanical strain forces being applied across the implant which, if notcorrected, can be a harbinger of future loosening and prosthesisfailure. In addition, the strain gauges 26 may be of the type whichindicates the strain which is being exhibited between two surfaces, suchas between the tibial side and the bone, the femoral side and the bone,the patellar side and the bone, between the prosthetic components(tibial, femoral and patellar) and the bone cement, or between thetibial, femoral, and patellar components themselves.

As shown in FIG. 6, strain gauges 26 may be positioned at variouslocations on the tibial component to detect strain encountered betweenthe tibial prosthesis and the surrounding tibial bone (and/or bonecement if present). Many tibial prostheses contain a stem that extendsinto the medullary canal of the tibia to enhance anchoring andstability. A decrease in strain in the tibial prosthesis and/or tibialbone cement may indicate that conditions are present that couldpotentially lead to bone resorbtion (loss) in all, or parts, of thetibial canal; bone resorbtion can lead to loosening of the prosthesis,or to tibial fracture (conversely, increased strain would favour bonegrowth in the region). Therefore, the strain sensors can provide anindication of the strain that is present in the tibial shaft and measurethe most important mechanical strain forces being applied across theimplant which, if mal-aligned or not corrected, have a high probabilityof resulting in loosening and prosthesis failure. An increase of strainmay also indicate bone hypertrophy (growth), which can be a source ofpain. The same dynamic exists in the interface between the femoral andpatellar prosthetic components (and/or bone cement) and the femur andpatellar; strain gauges 26 of the present invention can be used tomonitor for these purposes as well. “Real life” strain information wouldnot just be beneficial to the doctor and patient, who could use the datato determine the (positive and negative) effects of various activitieson prosthetic-bone health, but also to manufacturers who could use it todesign better prostheses.

In another embodiment shown in FIG. 7, one or more accelerometers 27 areprovided throughout the implant, including accelerometers 27Adistributed on and within the femoral condyle prosthesis, accelerometers26B distributed on and within the tibial plate (and stem if present) andtibial liner, and accelerometers 27C distributed on within the patellarprosthesis (patellar “button”). In some embodiments, the accelerometersare on/within the prosthetic components themselves (tibial, femur andpatellar segments), while in others the accelerometers are containedon/within the bone cement (if present) used to secure the prosthesis tothe surrounding bone, and in still other embodiments the accelerometersare contained on/within both the prosthetic components and the bonecement (PMMA).

In various embodiments, accelerometers may be positioned in a variety ofdifferent patterns within/on the prosthetic components based on theircontact locations with respect to the surrounding bone (femur, tibiaand/or patella), the surrounding bone cement (if present), the articularinterface between the different prosthetic components (tibial-femoraljoint and the patellar-femoral joint), and/or between sub-segments of acomponent (e.g. between the tibial plate and the tibial liner). Forexample, they may be arranged in the pattern of an X, as oval orconcentric rings around, or within, the various components or in variousother patterns, in order to collect accurate data experienced by theprosthetic components, the surrounding bone cement (if present), and (byextension) the surrounding bone (femur, tibia, patella) tissue.

Within various embodiments of the invention accelerometers are placedon/within the tibial component, femoral component, patellar prosthesis,and/or in the bone cement at a density of greater than one, two, three,four, five, six, seven, eight, nine, or ten sensors per squarecentimeter, or, per cubic centimeter of the device and/or the bonecement.

Accelerometers provide the benefit of being able to detect acceleration,vibration, shock, tilt, and rotation of various components. They permitthe ability to measure performance of the prosthesis 10 under variousconditions and over long periods of time.

During knee replacement surgery, the prosthetic joint will be movedthrough a full range of motion and stability testing to assessprosthetic function and mobility prior to surgical closure. Theaccelerometers 27 can provide the surgeon with accurate, numeric,quantitative range of motion data at that time; this data can becompared to expected values to assess efficacy of the implantationsurgery and can serve as a baseline value for comparison to functionalvalues obtained post-operatively. Any abnormalities in vibration(indicative of an inadequate anchoring of the prosthesis in thesurrounding bone), tilt (indicative of improper tracking and/oralignment of the tibial-femoral joint and the patellar-femoral joint),rotation (indicative of dislocation or subluxation), and/or range ofmotion can be addressed at this time and allow the surgeon to makeadjustments intra-operatively. Shortly after the knee has been replaced,the leg will be mobilized post-operatively, at first passively, thenactively; shortly after recovering from the procedure, the patient willbegin gradual weight bearing on the joint. The accelerometers 27 canmeasure the movement and tracking of the knee joint during movement,including during ambulation as the leg swings forward, hits the ground,plants, is lifted off the ground, and the body is propelled forward. Inaddition, the accelerometers can measure the impact of the foot hittingthe ground and the effect of the force being transferred through thetibia to the knee joint and any vibration, shock or rotation which mayoccur at different locations in the prosthesis 10. As the patientcontinues to improve their range of motion postoperatively, theacceleration experienced at different locations in the prosthetic kneejoint, can be monitored. It will be expected that as the patient healsfrom the surgery, activity levels will progressively increase,ambulation will improve and increase, steps will be more rapid (andfluid) and, in addition, greater stride length will be achieved witheach step. The effects of exercise and various activities can bemonitored by the various accelerometers 27 and can be compared topatient's subjective experiences to determine which life activities areimproving (or inhibiting) post-operative recovery and rehabilitation.

In another embodiment shown in FIG. 8, one or more position sensors 28are provided throughout the implant, including position sensors 28Adistributed on and within the femoral condyle prosthesis, positionsensors 26B distributed on and within the tibial plate (and stem ifpresent) and tibial liner, and position sensors 27C distributed onwithin the patellar prosthesis (patellar “button”). In some embodiments,the position sensors are on/within the prosthetic components themselves(tibial, femur and patellar segments), while in others the positionsensors are contained on/within the bone cement (if present) used tosecure the prosthesis to the surrounding bone, and in still otherembodiments the position sensors are contained on/within both theprosthetic components and the bone cement (PMMA).

In various embodiments, position sensors may be positioned in a varietyof different patterns within/on the prosthetic components based on theircontact locations with respect to the surrounding bone (femur, tibiaand/or patella), the surrounding bone cement (if present), the articularinterface between the different prosthetic components (tibial-femoraljoint and the patellar-femoral joint), and/or between sub-segments of acomponent (e.g. between the tibial plate and the tibial liner). Forexample, they may be arranged in the pattern of an X, as oval orconcentric rings around, or within, the various components or in variousother patterns, in order to collect accurate data experienced by theprosthetic components, the surrounding bone cement (if present), and (byextension) the surrounding bone (femur, tibia, patella) tissue.

Within various embodiments of the invention position sensors 28 areplaced on the tibial component, femoral component, patellar prosthesis,and/or in the bone cement at a density of greater than one, two, three,four, five, six, seven, eight, nine, or ten sensors per squarecentimeter, or, per cubic centimeter of the device and/or bone cement.

Positional sensors 28 as described herein can be utilized to provideaccurate positional data (intra-operatively and post-operatively),including the measurement of flexion and extension, to enhance theaccuracy of a physical exam by providing 3 dimensional data of theimplant, to detect full and partial dislocation (subluxation) of thetibial-femoral (knee) joint and/or the patella-femoral joint, and todetermine proper tracking of the knee joint and the patella.

In another embodiment shown in FIG. 9, one or more contact or pressuresensors 22 are provided throughout the implant, including contact orpressure sensors 22A distributed on and within (at various depths) thefemoral condyle articular surface, contact or pressure sensors 22Bdistributed on and within the tibial articular liner (at variousdepths), and contact or pressure sensors 27C distributed on within (atvarious depths) the patellar articular prosthesis (patellar “button”).

These sensors can also be utilized to detect progressive erosion of thevarious articular surfaces. The sensors 22 may be placed at progressivedepths in the tibial, femoral and patellar articular surface materials.They can also be activated when they are uncovered (or when the coveringsurface is worn away), to indicate the extent and depth of surface loss.

Such sensors can be utilized to estimate the effective remaininglifespan of the implant, and to compare the performance and design ofdifferent materials and implants.

B. Use of Knee Prosthesis, Medical Device or Kit to Deliver TherapeuticAgent(s)

As noted above, the present invention also provides knee prosthesis,medical devices and kits which comprise one or more sensors, and whichcan be utilized to release a therapeutic agent (e.g., a drug) to adesired location within the body. For example, anti-restenotic drugs(e.g., paclitaxel, sirolimus, or an analog or derivative of these), canbe administered by a knee prosthesis, medical device or kit. Withinpreferred embodiments one or more sensors (e.g., pressure sensors,contact sensors, and/or position sensors) can be utilized to determineappropriate placement of the desired drug, as well as the quantity ofdrug that is released at the desired site.

Within other embodiments of the invention a wide variety of additionaltherapeutic agents may be delivered (e.g., to prevent or treat aninfection or to treat another disease state), including for example:Anthracyclines (e.g., gentamycin, tobramycin, doxorubicin andmitoxantrone); Fluoropyrimidines (e.g., 5-FU); Folic acid antagonists(e.g., methotrexate); Podophylotoxins (e.g., etoposide); Camptothecins;Hydroxyureas, and Platinum complexes (e.g., cisplatin) (see e.g., U.S.Pat. No. 8,372,420 which is incorporated by reference in its entirety.Other therapeutic agents include beta-lactam antibiotics (e.g., thepenicillins, cephalosporins, carbacephems and carbapenems);aminoglycosides (e.g., sulfonamides, quinolones and the oxazolidinones);glycopeptides (e.g., vancomycin); lincosamides (e.g, clindamycin);lipopeptides; macrolides (e.g., azithromycin); monobactams; nitrofurans;polypeptides (e.g, bacitracin); and tetracyclines.

C. Use of a Knee Prosthesis, Medical Device or Kit Having Sensors toMeasure Degradation or Wearing of an Implant

As noted above, within various aspects of the present invention kneeprosthesis, medical devices and kits which can detect and monitor thedegradation of an implant. For example, within one embodiment of theinvention a method is provided for degradation of a knee replacement,medical device or kit, comprising the steps of a) providing to a subjecta knee replacement, medical device or kit having sensors as describedherein, and b) detecting a change in a sensor, and thus determiningdegradation of the knee replacement, medical device or kit. Withinvarious embodiments the sensor(s) can detect one or more physiologicaland/or locational parameters. Within another embodiment, the sensor(s)can detect contact, fluid flow, pressure and/or temperature. Within yetanother embodiment the sensors can detect a location within the subject.

When a knee prosthesis degrades or is damaged, sensors can detect achange so that a determination of damage and/or degradation can be made.For example, a sensor that was previously embedded within a polymerportion of a device, upon degradation may be exposed to fluid forces,and pressures where none existed before. If a sensor is eroded away, itmay move within the synovial cavity (i.e., away from where it hadpreviously been implanted). Hence, within preferred embodiments of theinvention degradation can be detected over a period of time.

D. Methods for Monitoring Infection in Knee Prosthesis, Medical Devicesand Kits

Within other embodiments knee prosthesis, medical devices and kits areprovided comprising one or more temperature and/or metabolic sensors.Such knee prosthesis, medical device or kits can be utilized to measurethe temperature of the knee prosthesis, medical device or kit, and inthe local tissue adjacent to the knee prosthesis, medical device or kit.Methods are also provided for monitoring changes in temperature overtime, in order to determine and/or provide notice (e.g., to a patientand/or healthcare provider) that an infection may be imminent.

In certain embodiments of the present invention, metabolic and physicalsensors can also be placed on or within the various components of atotal or partial knee prosthesis, medical device or kit in order tomonitor for rare, but potentially life-threatening complications of kneeprosthesis, medical device or kits. In some patients, the kneeprosthesis, medical device or kit and surrounding tissues can becomeinfected; typically from bacteria colonizing the patient's own skin thatcontaminate the surgical field (often Staphylococcus aureus orStaphylococcus epidermidis). Sensors such as temperature sensors(detecting temperature increases), pH sensors (detecting pH decreases),and other metabolic sensors can be used to suggest the presence ofinfection on or around the implant. For example, temperature sensors maybe included within one or more components of a knee prosthesis, medicaldevice or kit in order to allow early detection of infection could allowpreemptive treatment with antibiotics or surgical drainage and eliminatethe need to surgically remove the knee prosthesis, medical device orkit.

Hence, within one embodiment of the invention methods are provided fordetermining an infection associated with a knee prosthesis, medicaldevice or kit, comprising the steps of a) providing to a subject a kneeprosthesis, medical device or kit as described herein, wherein the kneeprosthesis, medical device or kit comprises at least one temperaturesensor and/or metabolic sensor, and b) detecting a change in saidtemperature sensor and/or metabolic sensor, and thus determining thepresence of an infection. Within various embodiments of the inventionthe step of detecting may be a series of detections over time, and achange in the sensor is utilized to assess the presence or developmentof an infection. Within further embodiments a change of 0.5%, 1.0%, or1.5% elevation of temperature or a metabolic factor over time (e.g.,0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4 hours, 12 hours, 1 day, or 2 days)can be indicative of the presence of an infection (or a developinginfection).

Within various embodiments of the invention an antibiotic may bedelivered in order to prevent, inhibit or treat an infection subsequentto its detection. Representative examples of suitable antibiotics arewell known, and are described above under Section B (the “TherapeuticAgents”).

E. Further Uses of Sensor-Containing Knee Prosthesis, Medical Devicesand Kits in Healthcare

Postoperative progress can be monitored (readings compared fromday-to-day, week-to-week, etc.) and the information compiled and relayedto both the patient and the attending physician allowing rehabilitationto be followed sequentially and compared to expected (typicalpopulation) norms. Within certain embodiments, a wearable deviceinterrogates the sensors on a selected or randomized basis, and capturesand/or stores the collected sensor data. This data may then bedownloaded to another system or device (as described in further detailbelow).

Integrating the data collected by the sensors described herein (e.g.,contact sensors, position sensors, strain gauges and/or accelerometers)with simple, widely available, commercial analytical technologies suchas pedometers and global positioning satellite (GPS) capability, allowsfurther clinically important data to be collected such as, but notrestricted to: extent of patient ambulation (time, distance, steps,speed, cadence), patient activity levels (frequency of activity,duration, intensity), exercise tolerance (work, calories, power,training effect), range of motion (discussed later) and prosthesisperformance under various “real world” conditions. It is difficult tooverstate the value of this information in enabling better management ofthe patient's recovery. An attending physician (or physiotherapist,rehabilitation specialist) only observes the patient episodically duringscheduled visits; the degree of patient function at the exact moment ofexamination can be impacted by a multitude of disparate factors such as:the presence or absence of pain, the presence or absence ofinflammation, stiffness, time of day, compliance and timing ofmedication use (pain medications, anti-inflammatories), recent activityand exercise levels, patient strength, mental status, language barriers,the nature of their doctor-patient relations knee, or even the patient'sability to accurately articulate their symptoms—to name just a few.Continuous monitoring and data collection can allow the patient and thephysician to monitor progress objectively by supplying objectiveinformation about patient function under numerous conditions andcircumstances, to evaluate how performance has been affected by variousinterventions (pain control, exercise, physiotherapy, anti-inflammatorymedication, rest, etc.), and to compare rehabilitation progress versusprevious function and future expected function. Better therapeuticdecisions and better patient compliance can be expected when both thedoctor and the patient have the benefit of observing the impact ofvarious treatment modalities on patient rehabilitation, activity,function and overall performance.

The sensors used for the contact, strain, accelerometers and positiondetection can be an acceptable type of those generally available (seee.g., U.S. Pat. Nos. 7,450,332; 7,463,997 and 7,924,267 which describevarious types of such sensors, including MEMs sensors that can act asstrain gauges, accelerometers and many other sensing functions). Theparticular sensor described in U.S. Pat. No. 7,450,332, which detectsfree fall of an object and motion of an object with respect to a gravityfield, would have particular benefits in being able to detect and storeall the forces acting on the leg and the full motion of the leg, duringpassive and active motion and when it is swinging in between steps, bothbefore, after and during impact with the ground.

As one example of the above, FIG. 4 illustrates the uses of the sensorsduring a physical examination of the patient and the different types ofdata which may be obtained from the sensors which have been implantedaccording to the teachings herein. The sensors provide evaluation dataon the range of motion (ROM) of the knee. Currently, ROM is usuallymeasured clinically by the physician passively moving the knee jointthrough a full range of motion during physical examination and recordingthe results (degrees of flexion, extension, abduction, adduction,external rotation, internal rotation and rotation in flexion). Motionsensors and accelerometers can be used to accurately determine the fullROM of the prosthetic knee joint intra-operatively (in case surgicaladjustment is necessary), during post-operative physical examination andduring normal daily activities between visits. As shown in FIG. 11A, oneprimary factor in the health of the knee is the angle X that the patientis able to achieve at various times during physical therapy as theyrecover from the surgery. As the angle X becomes smaller and smaller,the doctor can be assured that joint function is improving. By trackingangle X over time the physical therapist can monitor the progress of thepatient, assess whether scar tissue formation, subluxation, or otherpathology is limiting/affecting ROM of the knee, and change/implementtreatment as needed. With the sensors installed as indicated herein, thephysical therapist or physician does not need to guess the angle beingachieved, rather, if the leg is positioned adjacent to a read outcomputer, the exact angle can be known at the very moment that the jointis being clinically evaluated. On the other hand, if X does not continueto decrease, but remains large (or increases), the physical therapist orphysician can be alerted to problems which the patient may be having inrehabilitation or delayed recovery from the surgery and can investigateand/or take action sooner rather than later. Similarly, the embodimentof FIG. 11B indicates measurements that can be taken when the user holdsthe leg at exactly a 90° angle Y as shown. With the leg held firmly at90°, data can be collected from the various sensors throughout the legin order to determine the strain, the contact locations, accelerationand other data. The position sensors as used herein can alert thepatient that the leg is held at exactly 90° so that the collecting ofthe data can be accurate as data is collected at different times overseveral months as the patient is monitored. While flexion and extensionare illustrated in the sited figures, it should be obvious to one ofskill in the art that data can also be collected for medial-lateraljoint stability and for anterior-posterior stability, subluxation (ifpresent) and tracking of the knee joint and the patella. Additionally,ROM can also be monitored between patient visits by interpreting ROMgenerated during daily activities when the patient is at home.

As noted above, within other aspects of the invention methods areprovided for imaging a knee replacement or medical device as providedherein, comprising the steps of (a) detecting the location of one ormore sensors in a knee replacement or medical device; and (b) visuallydisplaying the location of said one or more sensors, such that an imageof the knee replacement or medical device is created. Within variousembodiments, the step of detecting may be done over time, and the visualdisplay may thus show positional movement over time. Within certainpreferred embodiments the image which is displayed is athree-dimensional image. Within other embodiment, the imaging techniquesmay be utilized post-operatively in order to examine the kneereplacement or medical device, and/or to compare operation and/ormovement of the device over time.

Certain exemplary embodiments will now be explained in more detail. Oneparticular benefit is the live and in-situ monitoring of the patient'srecovery and the implanted prosthesis 10. The sensors as describedherein are collecting data on a constant basis, during normal dailyactivities and even during the night if desired. Namely, the strain willbe measured, collected and stored on a regular basis over long periodsof time with particular measurements being taken at regular intervals.For example, the contact sensors can obtain and report data once every10 seconds, once a minute, or once a day. Other sensors will collectdata more frequently, such as several times a second. For example, itwould be expected that the acceleration and position data would becollected and stored several times a second. Other types of data mightonly need to be collected by the minute or by the hour. Still othersensors may collect data only when signaled by the patient to do so (viaan external signaling/triggering device) as part of “eventrecording”—i.e. when the patient experiences a particular event (e.g.pain, injury, instability, etc.)—and signals the device to obtain areading at that time in order to allow the comparison ofsubjective/symptomatic data to objective/sensor data in an effort tobetter understand the underlying cause or triggers of the patient'ssymptoms. Since the tibial stem contains a large internal portion which,might be hollow or a solid bar of metal, this internal structure hasmore than sufficient space in order to house one or more processorcircuits, CPUs, memory chips and other electrical circuits as well asantennas for sending and receiving the data. The processors can beprogrammed to collect data from the various sensors on any desiredschedule as set by the medical professional. All activity can becontinuously monitored post operation and the data collected and storedin the memory located inside the implant.

A patient will generally have regular medical checkups. When the patientgoes to the doctor's office for a medical checkup, the doctor will bringa reading device closely adjacent to the prosthesis 10, in this examplea knee replacement, in order to transfer the data from the internalcircuit inside the implant to the database in the physician's office.The use of wireless transmission using smartcards or other techniques isvery well known in the art and need not be described in detail. Examplesof such wireless transmission of data are provided in the publishedpatent applications and patents which have been described herein. Thedata which has been collected based on the patient's movement and use ofthe leg over the prior several weeks or even several months istransferred in a few moments from the memory which is positioned in theimplant to the doctor's computer or wireless device. The computertherefore analyzes the data for anomalies, unexpected changes over time,positive or negative trends, and other signs which may be indicative ofthe health of the patient and the operability of the prosthesis. Inaddition, the physician can collect data that details the record of allimpacts to the joint, including the magnitude and the direction of theacceleration. If the physician locates a high acceleration event, suchas the patient falling, or other physical activities or exercise, thephysician can be alerted to inquire of the patient of any problems theymay have had during a fall or, alternatively, warn the patient againsttoo vigorous an activity which may potentially cause damage to the kneeimplant. For example, if the patient has decided to go skiing orjogging, the doctor will be able to monitor the effect of such activityon the prosthesis 10, including the accelerations and strains during theevent itself. The doctor can then look at the health of the prosthesisin the hours and days after the event and compare it to data prior tothe event to determine if any particular event caused long term damage,such a separation of the prosthesis from the surrounding bone tissue orjoint subluxation, or if the activities subjected the prosthesis tostress/strain/impact forces beyond the manufacturer's performancespecifications for that particular artificial joint. Data can becollected and compared with respect to the ongoing and long termperformance of the prosthesis from the strain gauges, the contactsensors, the surface wear sensors, or other sensors which may bepresent.

In one alternative, the patient may also have such a reading device intheir home which collates the data from the prosthesis on a periodicbasis, such as once per day or once per week. As described above, thepatient may also be able to “trigger” a device reading (via an externalsignaling/triggering device) as part of “event recording.” Empoweringthe patient to follow their own rehabilitation—and enabling them to seethe positive (and negative) effects of various lifestyle choices ontheir health and rehabilitation—can be expected to improve complianceand improve patient outcomes. Furthermore, their experience can beshared via the web with other patients to compare their progress versusexpected “norms” for function and rehabilitation and alert them to signsand symptoms that should be brought to their doctor's attention. Theperformance of different implants can be compared in different patients(different sexes, weights, activity levels, etc.) to help manufacturersdesign better prostheses and assist orthopedic surgeons in the selectionof the right prosthesis for specific patient types. Payers, patients,manufacturers and physicians could all benefit from the collection ofthis comparative information. Lastly, data accumulated at home can becollected and transmitted via the Internet to the physician's office foranalysis—potentially eliminating unnecessary visits in some cases andencouraging immediate medical follow-up in others.

F. Generation of Power

Within certain aspects of the invention, a small electrical generationunit can be positioned along an outer, or alternatively an inner,surface of the implant. In particular, every time a user takes a step,there is a release of pressure and an increase of pressure inside theinternal structure of the implant. Using the appropriate piezoelectricmaterials or microelectric generators, a small amount of electricity canbe generated with each step that is taken. The electricity can be storedin capacitors also mounted inside the implant. The electricity can thenbe used to power the sensors that are positioned at the variouslocations inside the prosthesis.

A variety of techniques have been described for scavenging power fromsmall mechanical movements or mechanical vibration. See, for example,the article entitled “Piezoelectric Power Scavenging of MechanicalVibration Energy,” by U. K. Singh et al., as published in the AustralianMining Technology Conference, Oct. 2-4, 2007, pp. 111-118. This paperprovides examples of different types of power scavengers which canproduce electricity from very small motion and store the electricity forlater use. The above article also describes embodiments in whichpressure is applied and released from the particular structure in orderto produce electricity without the need for motion, but rather as aresult of the application of high pressure. As explained in theembodiments herein, force is applied to the internal structure of theimplant when the patient puts his weight on the leg during a step andsuch force can produce more than enough electric power to operate all ofthe sensors which are described herein. Other mechanisms that canproduce electricity from very small amounts of repetitive motion aredescribed U.S. Patent Application Publication No. 2010/0164705,published on Jul. 1, 2010. This patent application describes techniquesby which energy can be harvested in the rotation of a tire and then theharvested energy can be used to power a plurality of different sensorsand then, at selected time periods, the selected sensors can output thecollected data to a central collection site. Other sensors of this typeare described in issued U.S. Pat. No. 7,603,894, entitled “Self-PoweredTire Monitoring System.”

In one preferred embodiment, the electrical generation system ismotionless and relies solely on pressure that is applied during the stepand the release of that pressure when the step is completed and the legswings free for the next step. Since there is no motion, the patent willnot feel any sensation due to small changes in the position or length ofthe implant during the step. Rather, the length is kept constant and theelectricity is generated by piezoelectric structures or by internalsuspended structures which do not form part of the support structure ofthe implant.

After the electricity is generated by one or more generators, theelectricity is transmitted to any one of the variety of sensors which isdescribed herein. For example, it can be transmitted to the contactsensors 22, the strain gauges 26, the accelerometers 27, or thepositional sensors 28. It may also be transmitted to the other sensorsdescribed herein. The transmission of the power can be carried out byany acceptable technique. For example, if the sensor is physicallycoupled to the implant, electric wires may run from the generator to theparticular sensor. Alternatively, the electricity can be transmittedwirelessly in the same way that wireless smartcards receive power fromclosely adjacent power sources using the appropriate send and receiveantennas. Such send and receive techniques of electric power are alsodescribed in the publication and the patent applications and issued U.S.patent previously described, all of which are incorporated herein byreference.

G. Medical Imaging and Self-Diagnosis of Assemblies Comprising KneeReplacements; Predictive Analysis and Predictive Maintenance

The present invention provides knee replacements which are capable ofimaging through the use of sensors over a wide variety of conditions.For example, within various aspects of the invention methods areprovided for imaging a knee replacement (or portion thereof (e.g., amedical device or kit as described herein) or an assembly comprising aknee replacement, medical device or kit (as described herein) withsensors, comprising the steps of detecting the changes in sensors in,on, and or within a knee replacement, medical device or kit over time,and wherein the knee replacement, medical device or kit comprisessensors at a density of greater than 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 10sensors per square centimeter. Within other aspects the knee replacementmedical device or kit comprises sensors at a density of greater than 1,2, 3, 4, 5, 6, 7, 8, 9, 10 or 10 sensors per cubic centimeter. Withineither of these embodiments there can be less than 50, 75, 100, or 100sensors per square centimeter, or per cubic centimeter. Within variousembodiments the at least one or more of the sensors may be placedrandomly, or at one or more specific locations within the kneereplacement, medical device, or kit as described herein. As noted above,a wide variety of sensors can be utilized therein, including forexample, contact sensors, strain gauge sensors, pressure sensors, fluidpressure sensors, position sensors, pulse pressure sensors, blood volumesensors, blood flow sensors, blood chemistry sensors, blood metabolicsensors, mechanical stress sensors, and temperature sensors.

For example, a knee replacement, medical device, or kit comprisingsensors as described herein can be utilized to image knee anatomythrough sensors which can detect positional movement. The sensors usedcan also include accelerometers and motion sensors to detect movement ofthe knee replacement due to a variety of physical changes. Changes inthe position of the accelerometers and/or motion sensors over time canbe used as a measurement of changes in the position of the kneereplacement over time. Such positional changes can be used as asurrogate marker of knee anatomy—i.e. they can form an “image’ of theknee replacement to provide information on the size, shape and locationof changes to the knee replacement, and/or knee replacementmovement/migration. For example, loosening of the knee prosthesis canresult in unwanted movement of the prosthesis relative to bone in whichit is implanted during activity and weight bearing. By utilizing sensorsin the present invention, it is possible to determine the location ofthe unwanted movement and the degree of movement present duringdifferent motions and activities. Similarly, monitoring changes in thejoint space (i.e. the change in the space separating the femoral and thetibial components) over time can be used as an indicator of jointsurface (femoral side and/or tibial side) erosion and wear. Finally,following the movement of the sensors throughout their range of motioncan provide a dynamic “image” of the joint; allowing the clinician tomonitor both improvement and decline in joint function (and surroundingtissues) over time.

H. Methods of Monitoring Assemblies Comprising Knee Replacements

As noted above, the present invention also provides methods formonitoring one or more of the knee replacement assemblies providedherein. For example, FIG. 10 illustrates a monitoring system usable withthe knee replacement 10 as of the type shown in any one of the Figuresdescribed above. The monitoring system includes a sensor (e.g., 22, 26,27 and/or 28) an interrogation module 124, and a control unit 126. Thesensor (e.g., 22, 26, 27 and/or 28) can be passive, wireless type whichcan operate on power received from a wireless source. Such sensors ofthis type are well known in the art and widely available. A pressuresensor of this type might be a MEMS pressure sensor, for example, PartNo. LPS331AP, sold on the open market by STMicroelectronics. MEMSpressure sensors are well known to operate on very low power andsuitable to remain unpowered and idle for long periods of time. They canbe provided power wirelessly on an RF signal and, based on the powerreceived wirelessly on the RF signal, perform the pressure sensing andthen output the sensed data.

In one embodiment, an electrical generation system (as described above)is provided that can be utilized to power the sensors described herein.During operation, as shown in FIG. 10, an interrogation module 124outputs a signal 128. The signal 128 is a wireless signal, usually inthe RF band, that contains power for the sensor (e.g., 22, 26, 27 and/or28) as well as an interrogation request that the sensors perform asensing. Upon being interrogated with the signal 128, the sensor (e.g.,22, 26, 27 and/or 28) powers up and stores power in onboard capacitorssufficient to maintain operation during the sensing and data reporting.Such power receiving circuits and storing on onboard capacitors are wellknown in the art and therefore need not be shown in detail. Theappropriate sensing is carried out by the sensor (e.g., 22, 26, 27and/or 28) and then the data is output from the sensor back to theinterrogation module 124 on a signal 130, where it is received at aninput port of the integration module.

According to one embodiment, sufficient signal strength is provided inthe initial signal 128 to provide power for the sensor and to carry outthe sensing operation and output the signal back to the interrogationmodule 124. In other embodiments, two or more signals 128 are sent, eachsignal providing additional power to the sensor to permit it to completethe sensing operation and then provide sufficient power to transfer thedata via the signal path 130 back to the interrogation module 124. Forexample, the signal 128 can be sent continuously, with a sensing requestcomponent at the first part of the signal and then continued providing,either as a steady signal or pulses to provide power to operate thesensor. When the sensor is ready to output the data, it sends a signalalerting the interrogation module 124 that data is coming and the signal128 can be turned off to avoid interference. Alternatively, theintegration signal 128 can be at a first frequency and the output signal130 at a second frequency separated sufficiently that they do notinterfere with each other. In a preferred embodiment, they are both thesame frequency so that the same antenna on the sensor can receive thesignal 128 and send signal 130.

The interrogation signal 128 may contain data to select specific sensorson the knee replacement. For example, the signal 128 may power up allsensors on the knee replacement at the same time and then send requestsfor data from each at different selected times so that with oneinterrogation signal 128 provided for a set time, such as 1-2 seconds,results in each of the sensors on the knee replacement collecting dataduring this time period and then, at the end of the period, reportingthe data out on respective signals 130 at different times over the next0.5 to 2 seconds so that with one interrogation signal 128, the datafrom all sensors 22 is collected.

The interrogation module 124 is operating under control of the controlunit 126 which has a microprocessor for the controller, a memory, an I/Ocircuit to interface with the interrogation module and a power supply.The control unit may output data to a computer or other device fordisplay and use by the physician to treat the subject.

FIG. 11 illustrates the operation according to a preferred embodimentwithin a subject. The subject has an outer skin 132. As illustrated inFIG. 13, the interrogation module 124 and control unit 126 arepositioned outside the skin 132 of the subject. The interrogation signal128 passes through the skin of the subject with a wireless RF signal,and the data is received on a wireless RF signal 130 from the sensor(e.g., 22, 26, 27 and/or 28) back to the interrogation module 124. Whilethe wireless signal can be in any frequency range, an RF range ispreferred. A frequency in the VLF to LF ranges of between 3-1300 kHz ispreferred to permit the signal to be carried to sufficient depth insidethe body with low power, but frequencies below 3 kHz and above 1300 kHzcan also be used. The sensing does not require a transfer of largeamounts of data and low power is preferred; therefore, a low frequencyRF signal is acceptable. This also avoids competition from andinadvertent activation by other wireless signal generators, such as bluetooth, cell phones and the like.

I. Collection, Transmission, Analysis, and Distribution of Data fromAssemblies Comprising Knee Replacements

FIG. 12 illustrates one embodiment of an information and communicationtechnology (ICT) system 800 arranged to process sensor data (e.g., datafrom sensor (e.g., 22, 26, 27 and/or 28) of any one of Figures providedherein). In FIG. 12, the ICT system 800 is illustrated to includecomputing devices that communicate via a network 804, however in otherembodiments, the computing devices can communicate directly with eachother or through other intervening devices, and in some cases, thecomputing devices do not communicate at all. The computing devices ofFIG. 12 include computing servers 802, control units 126, interrogationunits 124, and other devices that are not shown for simplicity.

In FIG. 12, one or more sensors (e.g., 22, 26, 27 and/or 28) communicatewith an interrogation module 124. The interrogation module 124 of FIG.12 is directed by a control unit 126, but in other cases, interrogationmodules 124 operates autonomously and passes information to and fromsensors 22. One or both of the interrogation module 124 and control unit126 can communicate with the computing server 802.

Within certain embodiments, the interrogation module and/or the controlunit may be a wearable device on the subject. The wearable device (e.g.,a watch-like device, glasses, a wrist-band, or other device that may becarried or worn by the subject) can interrogate the sensors over a set(or random) period of time, collect the data, and forward the data on toone or more networks (804). Furthermore, the wearable device may collectdata of its own accord which can also be transmitted to the network.Representative examples of data that may be collected include location(e.g., a GPS), body or skin temperature, and other physiologic data(e.g., pulse). Within yet other embodiments, the wearable device maynotify the subject directly of any of a number of prescribed conditions,including but not limited to possible or actual failure of the device.

The information that is communicated between an interrogation module 124and a sensor (e.g., 22, 26, 27 and/or 28) may be useful for manypurposes as described herein. In some cases, for example, sensor datainformation is collected and analyzed expressly for the health of anindividual subject. In other cases, sensor data is collected andtransmitted to another computing device to be aggregated with other data(for example, the sensor data from 22 may be collected and aggregatedwith other data collected from a wearable device (e.g., a device thatmay, in certain embodiments, include GPS data and the like).

FIG. 12 illustrates aspects of a computing server 802 as a cooperativebank of servers further including computing servers 802 a, 802 b, andone or more other servers 802 n. It is understood that computing server802 may include any number of computing servers that operateindividually or collectively to the benefit of users of the computingservers.

In some embodiments, the computing servers 802 are arranged as cloudcomputing devices created in one or more geographic locations, such asthe United States and Canada. The cloud computing devices may be createdas MICROSOFT AZURE cloud computing devices or as some other virtuallyaccessible remote computing service.

An interrogation module 124 and a control unit 126 are optionallyillustrated as communicating with a computing server 802. Via theinterrogation module 124 or control unit 126, sensor data is transferredto (and in addition or alternatively from) a computing server 802through network 804.

The network 804 includes some or all of cellular communication networks,conventional cable networks, satellite networks, fiber-optic networks,and the like configured as one or more local area networks, wide areanetworks, personal area networks, and any other type of computingnetwork. In a preferred embodiment, the network 804 includes anycommunication hardware and software that cooperatively works to permitusers of computing devices to view and interact with other computingdevices.

Computing server 802 includes a central processing unit (CPU) digitalsignal processing unit (DSP) 808, communication modules 810,Input/Output (I/O) modules 812, and storage module 814. The componentsof computing server 802 are cooperatively coupled by one or more buses816 that facilitate transmission and control of information in andthrough computing server 802. Communication modules 810 are configurableto pass information between the computer server 802 and other computingdevices (e.g., computing servers 802 a, 802 b, 802 n, control unit 126,interrogation unit 124, and the like). I/O modules 812 are configurableto accept input from devices such as keyboards, computer mice,trackballs, and the like. I/O modules 812 are configurable to provideoutput to devices such as displays, recorders, LEDs, audio devices, andthe like.

Storage module 814 may include one or more types of storage media. Forexample, storage module 814 of FIG. 12 includes random access memory(RAM) 818, read only memory (ROM) 810, disk based memory 822, opticalbased memory 8124, and other types of memory storage media 8126. In someembodiments one or more memory devices of the storage module 814 hasconfigured thereon one or more database structures. The databasestructures may be used to store data collected from sensors 22.

In some embodiments, the storage module 814 may further include one ormore portions of memory organized a non-transitory computer-readablemedia (CRM). The CRM is configured to store computing instructionsexecutable by a CPU 808. The computing instructions may be stored as oneor more files, and each file may include one or more computer programs.A computer program can be standalone program or part of a largercomputer program. Alternatively or in addition, each file may includedata or other computational support material for an application thatdirects the collection, analysis, processing, and/or distribution ofdata from sensors (e.g., knee replacement sensors). The sensor dataapplication typically executes a set of instructions stored oncomputer-readable media.

It will be appreciated that the computing servers shown in the figuresand described herein are merely illustrative and are not intended tolimit the scope of the present invention. Computing server 802 may beconnected to other devices that are not illustrated, including throughone or more networks such as the Internet or via the Web that areincorporated into network 804. More generally, a computing system ordevice (e.g., a “client” or “server”) or any part thereof may compriseany combination of hardware that can interact and perform the describedtypes of functionality, optionally when programmed or otherwiseconfigured with software, including without limitation desktop or othercomputers, database servers, network storage devices and other networkdevices, PDAs, cell phones, wireless phones, glasses, wrist-bands,pagers, electronic organizers, Internet appliances, television-basedsystems (e.g., using set-top boxes and/or personal/digital videorecorders), and various other products that include appropriateinter-communication capabilities. In addition, the functionalityprovided by the illustrated system modules may in some embodiments becombined in fewer modules or distributed in additional modules.Similarly, in some embodiments the functionality of some of theillustrated modules may not be provided and/or other additionalfunctionality may be available.

In addition, while various items are illustrated as being stored inmemory or on storage while being used, these items or portions of themcan be transferred between memory and other storage devices for purposesof memory management and/or data integrity. In at least someembodiments, the illustrated modules and/or systems are softwaremodules/systems that include software instructions which, when executedby the CPU/DSP 808 or other processor, will program the processor toautomatically perform the described operations for a module/system.Alternatively, in other embodiments, some or all of the software modulesand/or systems may execute in memory on another device and communicatewith the illustrated computing system/device via inter-computercommunication.

Furthermore, in some embodiments, some or all of the modules and/orsystems may be implemented or provided in other manners, such as atleast partially in firmware and/or hardware means, including, but notlimited to, one or more application-specific integrated circuits(ASICs), standard integrated circuits, controllers (e.g., by executingappropriate instructions, and including microcontrollers and/or embeddedcontrollers), field-programmable gate arrays (FPGAs), complexprogrammable logic devices (CPLDs), and the like. Some or all of thesystems, modules, or data structures may also be stored (e.g., assoftware instructions or structured data) on a transitory ornon-transitory computer-readable storage medium 814, such as a hard disk822 or flash drive or other non-volatile storage device 8126, volatile818 or non-volatile memory 810, a network storage device, or a portablemedia article (e.g., a DVD disk, a CD disk, an optical disk, a flashmemory device, etc.) to be read by an appropriate input or output systemor via an appropriate connection. The systems, modules, and datastructures may also in some embodiments be transmitted as generated datasignals (e.g., as part of a carrier wave or other analog or digitalpropagated signal) on a variety of computer readable transmissionmediums, including wireless-based and wired/cable-based mediums. Thedata signals can take a variety of forms such as part of a single ormultiplexed analog signal, as multiple discrete digital packets orframes, as a discrete or streaming set of digital bits, or in some otherform. Such computer program products may also take other forms in otherembodiments. Accordingly, the present invention may be practiced withother computer system configurations.

In FIG. 12, sensor data from, e.g., sensor (e.g., 22, 26, 27 and/or 28)is provided to computing server 802. Generally speaking, the sensordata, represents data retrieved from a known subject and from a knownsensor. The sensor data may possess include or be further associatedwith additional information such as the USI, UDI, a time stamp, alocation (e.g., GPS) stamp, a date stamp, and other information. Thedifferences between various sensors is that some may include more orfewer data bits that associate the data with a particular source,collection device, transmission characteristic, or the like.

In some embodiments, the sensor data may comprise sensitive informationsuch as private health information associated with a specific subject.Sensitive information, for example sensor data from sensor (e.g., 22,26, 27 and/or 28), may include any information that an associated partydesires to keep from wide or easy dissemination. Sensitive informationcan stand alone or be combined with other non-sensitive information. Forexample, a subject's medical information is typically sensitiveinformation. In some cases, the storage and transmission of a subject'smedical information is protected by a government directive (e.g., law,regulation, etc.) such as the U.S. Health Insurance Portability andAccountability Act (KNEEPA).

As discussed herein, a reference to “sensitive” information includesinformation that is entirely sensitive and information that is somecombination of sensitive and non-sensitive information. The sensitiveinformation may be represented in a data file or in some other format.As used herein, a data file that includes a subject's medicalinformation may be referred to as “sensitive information.” Otherinformation, such as employment information, financial information,identity information, and many other types of information may also beconsidered sensitive information.

A computing system can represent sensitive information with an encodingalgorithm (e.g., ASCII), a well-recognized file format (e.g., PDF), orby some other format. In a computing system, sensitive information canbe protected from wide or easy dissemination with an encryptionalgorithm.

Generally speaking, sensitive information can be stored by a computingsystem as a discrete set of data bits. The set of data bits may becalled “plaintext.” Furthermore, a computing system can use anencryption process to transform plaintext using an encryption algorithm(i.e., a cipher) into a set of data bits having a highly unreadablestate (i.e., cipher text). A computing system having knowledge of theencryption key used to create the cipher text can restore theinformation to a plaintext readable state. Accordingly, in some cases,sensitive data (e.g., sensor data 806 a, 806 b) is optionally encryptedbefore being communicated to a computing device.

In one embodiment, the operation of the information and communicationtechnology (ICT) system 800 of FIG. 12 includes one or more sensor datacomputer programs stored on a computer-readable medium. The computerprogram may optionally direct and/or receive data from one or more kneereplacement sensors implanted in one or more subjects. A sensor datacomputer program may be executed in a computing server 802.Alternatively, or in addition, a sensor data computer program may beexecuted in a control unit 126, an interrogation unit 124.

In one embodiment, a computer program to direct the collection and useof knee replacement sensor data is stored on a non-transitorycomputer-readable medium in storage module 814. The computer program isconfigured to identify a subject who has a wireless knee replacementinserted in his or her body. The wireless knee replacement may includeone or more wireless sensor

In some cases, the computer program identifies one subject, and in othercases, two or more subjects are identified. The subjects may each haveone or more wireless knee replacements, and each wireless kneereplacement may have one or more wireless sensors of the type describedherein.

The computer program is arranged to direct the collection of sensor datafrom the wireless knee replacement devices. The sensor data is generallycollected with a wireless interrogation unit 124. In some cases, theprogram communicates with the wireless interrogation unit 124. In othercases, the program communicates with a control unit 126, which in turndirects a wireless interrogation unit 124. In still other cases, someother mechanism is used direct the collection of the sensor data.

Once the sensor data is collected, the data may be further processed.For example, in some cases, the sensor data includes sensitive subjectdata, which can be removed or disassociated with the data. The sensordata can be individually stored (e.g., by unique sensor identificationnumber, device number, etc.) or aggregated together with other sensordata by sensor type, time stamp, location stamp, date stamp, subjecttype, other subject characteristics, or by some other means.

The following pseudo-code description is used to generally illustrateone exemplary algorithm executed by a computing server 802 and generallydescribed herein with respect to FIG. 12:

Start Open a secure socket layer (SSL) Identify a subject Communicatewith a predetermined control unit Request sensor data from the subjectvia the control unit Receive sensor data If the sensor data is encryptedTHEN decrypt the sensor data Store encrypted data in the selectedstorage locations Aggregate the sensor data with other sensor data Storeencrypted data in the selected storage locations Maintain a record ofthe storage transaction Perform post storage actions End

Those skilled in the art will recognize that it is common within the artto implement devices and/or processes and/or systems, and thereafter useengineering and/or other practices to integrate such implemented devicesand/or processes and/or systems into more comprehensive devices and/orprocesses and/or systems. That is, at least a portion of the devicesand/or processes and/or systems described herein can be integrated intoother devices and/or processes and/or systems via a reasonable amount ofexperimentation. Those having skill in the art will recognize thatexamples of such other devices and/or processes and/or systems mightinclude—as appropriate to context and application—all or part of devicesand/or processes and/or systems of (a) an air conveyance (e.g., anairplane, rocket, helicopter, etc.), (b) a ground conveyance (e.g., acar, truck, locomotive, tank, armored personnel carrier, etc.), (c) abuilding (e.g., a home, warehouse, office, etc.), (d) an appliance(e.g., a refrigerator, a washing machine, a dryer, etc.), (e) acommunications system (e.g., a networked system, a telephone system, aVoice over IP system, etc.), (f) a business entity (e.g., an InternetService Provider (ISP) entity such as Comcast Cable, Qwest, SouthwesternBell, etc.), or (g) a wired/wireless services entity (e.g., Sprint,Cingular, Nextel, etc.), etc.

In certain cases, use of a system or method may occur in a territoryeven if components are located outside the territory. For example, in adistributed computing context, use of a distributed computing system mayoccur in a territory even though parts of the system may be locatedoutside of the territory (e.g., relay, server, processor, signal-bearingmedium, transmitting computer, receiving computer, etc. located outsidethe territory).

A sale of a system or method may likewise occur in a territory even ifcomponents of the system or method are located and/or used outside theterritory. Further, implementation of at least part of a system forperforming a method in one territory does not preclude use of the systemin another territory.

In conclusion, prosthetic knee replacements utilizing a variety ofsensors can be utilized to serve a variety of critical clinicalfunctions, such as safe, accurate and less traumatic placement anddeployment of the knee replacement, procedural and post-operative “realtime” imaging of knee replacement and the surrounding anatomy, thedevelopment of knee replacement complications, and the patient's overallhealth status. Currently, post-operative (both in hospital andout-patient) evaluation of knee replacement patients is through patienthistory, physical examination and medical monitoring that issupplemented with diagnostic imaging studies as required. However, mostof the patient's recuperative period occurs between hospital and officevisits and the majority of data on daily function goes uncaptured;furthermore, monitoring patient progress through the use of somediagnostic imaging technology can be expensive, invasive and carry itsown health risks (the use of nuclear isotopes or certain dyes). It can,therefore, be very difficult to accurately measure and follow thedevelopment or worsening of symptoms and evaluate “real life” kneereplacement performance, particularly as they relate to patient activitylevels, exercise tolerance, and the effectiveness of rehabilitationefforts and medications.

At present, neither the physician nor the patient has access to the typeof “real time,” continuous, objective, knee replacement performancemeasurements that they might otherwise like to have. Being able tomonitor in situ knee replacement function, integrity, anatomy andphysiology can provide the physician with valuable objective informationduring office visits; furthermore, the patient can take additionalreadings at home at various times (e.g. when experiencing pain, duringexercise, after taking medications, etc.) to provide importantcomplementary clinical information to the doctor (which can be sent tothe healthcare provider electronically even from remote locations). Fromthe perspective of the patient, being able to monitor many of these sameparameters at home allows them to take a more proactive role in theircare and recovery and provide him or her with either an early warningindicator to seek medical assistance or with reassurance.

In one alternative, the patient may have a reading device in their homewhich collates the data from the knee replacement on a periodic basis,such as once per day or once per week. In addition to empowering thepatient to follow their own rehabilitation—and enabling them to see thepositive (and negative) effects of various lifestyle choices on theirhealth and rehabilitation—such information access can be expected toimprove compliance and improve patient outcomes. For example, withincertain embodiments the devices and systems provided herein can instructor otherwise notify the patient, or a permitted third-party as todeviations (e.g., greater than 10%, 20%, 25%, 50%, 70%, and or 100%)from normal, and/or, set parameters. Furthermore, their recoveryexperience can be shared via the web with other patients to comparetheir progress versus expected “norms” for function and rehabilitationand alert them to signs and symptoms that should be brought to theirdoctor's attention. From a public health perspective, the performance ofdifferent knee replacements can be compared in different patients(different sexes, disease severity, activity levels, concurrent diseasessuch as hypertension and diabetes, smoking status, obesity, etc.) tohelp manufacturers design better knee replacements and assist physiciansin the selection of the right knee replacement for a specific patienttypes. Payers, patients, manufacturers and physicians could all benefitfrom the collection of this comparative information. Poor and dangerousproducts could be identified and removed from the market and objectivelong-term effectiveness data collected and analyzed. Lastly, dataaccumulated at home can be collected and transmitted via the Internet tothe physician's office for analysis—potentially eliminating unnecessaryvisits in some cases and encouraging immediate medical follow-up inothers.

The following are some specific numbered embodiments of the systems andprocesses disclosed herein. These embodiments are exemplary only. Itwill be understood that the invention is not limited to the embodimentsset forth herein for illustration, but embraces all such forms thereofas come within the scope of the above disclosure.

1) A knee replacement prosthesis comprising:

at least one of a tibial component, a patellar prosthesis, and a femoralcomponent; and

a plurality of sensors coupled to at least one of the tibial component,patellar prosthesis, and femoral component.

2) The knee replacement prosthesis of embodiment 1 wherein the pluralityof sensors includes a sensor on the tibial component.

3) The knee replacement prosthesis of embodiment 1 wherein the pluralityof sensors includes a sensor on the patellar prosthesis.

4) The knee replacement prosthesis of embodiment 1 wherein the pluralityof sensors includes a sensor on the femoral component.

5) The knee replacement prosthesis according to any one of embodiments 1to 4 wherein said sensor is selected from the group consisting ofaccelerometers, pressure sensors, contact sensors, position sensors,chemical microsensors, tissue metabolic sensors, mechanical stresssensors and temperature sensors.

6) The knee replacement prosthesis according to embodiment 5 whereinsaid accelerometer detects acceleration, tilt, vibration, shock and orrotation.

7) The knee replacement prosthesis of embodiment 1 wherein the pluralityof sensors includes contact sensors positioned on the femoral component.

8) The knee replacement prosthesis of embodiment 1 wherein the pluralityof sensors includes a plurality of contact sensors positioned on thepatellar component.

9) The knee replacement prosthesis of embodiment 1 wherein the pluralityof sensors includes a plurality of contact sensors positioned on thetibial component.

10) A medical device, comprising a femoral component of a kneereplacement prosthesis and a plurality of sensors coupled to saidfemoral component.

11) A medical device, comprising a patellar prosthesis of a kneereplacement prosthesis and a plurality of sensors coupled to saidpatellar prosthesis.

12) A medical device, comprising a tibial component of a kneereplacement and a plurality of sensors coupled to said tibial component.

13) The medical device according to any one of embodiments 10 to 12,wherein said sensors appear within and/or on the surface of said medicaldevice.

14) The medical device according to any one of embodiments 10 to 13wherein said sensor is selected from the group consisting ofaccelerometers, pressure sensors, contact sensors, position sensors,chemical microsensors, tissue metabolic sensors, mechanical stresssensors and temperature sensors.

15) The medical device according to embodiment 14 wherein saidaccelerometer detects acceleration, tilt, vibration, shock and orrotation.

16) The knee replacement prosthesis according to any one of embodiments1 to 9 or medical device according to any one of embodiments 10 to 15further comprising:

an electronic processor positioned upon and/or inside at least one ofthe tibial component, patellar prosthesis and/or the femoral componentthat is electrically coupled to sensors.

17) The knee replacement prosthesis or medical device of embodiment 16wherein the electric coupling is a wireless coupling.

18) The knee replacement prosthesis or medical device of embodiment 17further including:

a memory coupled to the electronic processor and positioned upon and/orinside the at least one of tibial component, patellar prosthesis andfemoral component.

19) The knee replacement prosthesis or medical device according to anyone of embodiments 1 to 18 wherein said sensor is a plurality of sensorswhich are positioned on or within said knee replacement at a density ofgreater than 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 20 sensors per squarecentimeter.

20) The knee replacement or medical device according to any one ofembodiments 1 to 19 wherein said sensor is a plurality of sensors whichare positioned on or within said knee replacement at a density ofgreater than 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 20 sensors per cubiccentimeter.

21) A method comprising:

obtaining contact data from contact sensors positioned at a plurality oflocations between on and/or within a knee replacement prosthesis ormedical devices according to any one of embodiments 1 to 20 of apatient;

storing the data in a memory device located on or within the kneereplacement prosthesis or medical device; and

transferring the data from the memory to a location outside the kneereplacement prosthesis or medical device.

22) The method according to embodiment 22 further including:

obtaining strain data from strain sensors positioned at a plurality oflocations on the knee replacement prosthesis or medical device of apatient;

storing the strain data in a memory located in said knee replacementprosthesis or medical device; and

transferring the strain data from the memory to a memory in locatedoutside the knee replacement prosthesis or medical device.

23) The method according to embodiment 22 further including:

obtaining contact data from contact sensors positioned in a kneereplacement prosthesis or medical device according to any one ofembodiments 1 to 19 of a patient;

storing the contact data in a memory located in the knee replacementprosthesis or medical device; and

transferring the data from the memory to a memory in a location outsideof the knee replacement prosthesis or medical device.

24) A method comprising:

obtaining acceleration data from accelerometers positioned at aplurality of locations on a knee replacement prosthesis or medicaldevice according to any one of embodiments 1 to 19 located in-situ inthe knee of a patient;

storing the acceleration data in a memory located in the kneereplacement prosthesis or medical device; and

transferring the acceleration data from the said memory in the kneereplacement prosthesis or medical device to a memory in a locationoutside the knee replacement prosthesis or medical device.

25) A kit comprising the knee replacement prosthesis or medical deviceaccording to any one of embodiments 1 to 19, further comprising bonecement and/or bone screws comprising one or more sensors.

26) The kit according to embodiment 25 wherein said one or more sensorsare selected from the group consisting of accelerometers, pressuresensors, contact sensors, position sensors, chemical microsensors,tissue metabolic sensors, mechanical stress sensors and temperaturesensors.

27) The kit according to embodiments 25 or 26 wherein said sensorsappear on said prosthesis or medical device at a density of greater than1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 20 sensors per square centimeter.

28) The knee replacement, medical device, or kit according to any one ofembodiments 1-20 or 25-27 wherein the one or more of the sensors areplaced randomly within the knee replacement, medical device or kit.Within other embodiments said sensors can be placed at specificlocations within the knee replacement, medical device or kit.

29) A method for detecting and/or recording an event in a subject with aknee replacement or medical device as provided in any one of embodiments1 to 28, comprising the step of interrogating at a desired point in timethe activity of one or more sensors within the knee replacement ormedical device, and recording said activity.

30) The method according to embodiment 29 wherein the step ofinterrogating is performed by a subject which has an implanted kneereplacement or medical device.

31) The method according to embodiment 30 wherein said recording isperformed on a wearable device.

32) The method according to any one of embodiments 29 to 31, whereinsaid recording is provided to a health care provider.

33) A method for imaging a knee replacement, medical device or kitaccording to any one of embodiments 1 to 20 or 25 to 27, comprising thesteps of

-   -   (a) detecting the location of one or more sensors in a knee        replacement, medical device, or kit according to any one of        embodiments 1 to 20 or 25 to 27; and    -   (b) visually displaying the location of said one or more        sensors, such that an image of the knee replacement or medical        device is created.

34) The method according to embodiment 33 wherein the step of detectingoccurs over time.

35) The method according to embodiment 34, wherein said visual displayshows changes in the positions of said sensors over time.

36) The method according to any one of embodiments 33 to 35 wherein saidvisual display is a three-dimensional image of said knee replacement ormedical device.

37) A method for inserting a knee replacement, medical device or kitaccording to any one of embodiments 1 to 20 or 25 to 27, comprising thesteps of

-   -   (a) inserting a medical device according to any one of        embodiments 1 to 20 or 25 to 27 into a subject; and    -   (b) imaging the placement of said medical device according to        the method of any one of embodiments 33 to 36.

38) A method for examining a knee replacement, medical device or kitaccording to any one of embodiments 1 to 20 or 25 to 27 which has beenpreviously inserted into a patient, comprising the step of imaging theknee replacement or medical device according to the method of any one ofembodiments 33 to 36.

39) A method of monitoring a knee replacement, medical device, or kitwithin a subject, comprising:

transmitting a wireless electrical signal from a location outside thebody to a location inside the subject's body;

receiving the signal at a sensor positioned on a knee replacement,medical device, or kit according to any one of embodiments 1 to 20 or 25to 27 located inside the body;

powering the sensor using the received signal;

sensing data at the sensor; and

outputting the sensed data from the sensor to a receiving unit locatedoutside of the body.

40) The method according to embodiment 39 wherein said receiving unit isa watch, wrist band, cell phone or glasses.

41) The method according to embodiments 39 or 40 wherein said receivingunit is located within a subject's residence or office.

42) The method according to embodiments any one of embodiments 39 to 41wherein said sensed data is provided to a health care provider.

43) The method according to any one of embodiments 39 to 42 wherein saidsensed data is posted to one or more websites.

44) A non-transitory computer-readable storage medium whose storedcontents configure a computing system to perform a method, the methodcomprising:

identifying a subject, the identified subject having at least onewireless knee replacement, medical device, or kit according to any oneof embodiments 1 to 20 or 25 to 27, each wireless knee replacement,medical device, or kit having one or more wireless sensors;

directing a wireless interrogation unit to collect sensor data from atleast one of the respective one or more wireless sensors; and

receiving the collected sensor data.

45) The non-transitory computer-readable storage medium of embodiment 44whose stored contents configure a computing system to perform a method,the method further comprising:

identifying a plurality of subjects, each identified subject having atleast one wireless knee replacement, medical device, or kit, eachwireless knee replacement, medical device, or kit having one or morewireless sensors;

directing a wireless interrogation unit associated with each identifiedsubject to collect sensor data from at least one of the respective oneor more wireless sensors;

receiving the collected sensor data; and

aggregating the collected sensor data.

46) The non-transitory computer-readable storage medium of embodiment 44whose stored contents configure a computing system to perform a method,the method further comprising:

removing sensitive subject data from the collected sensor data; and

parsing the aggregated data according to a type of sensor.

47) The non-transitory computer-readable storage medium of embodiment 44whose stored contents configure a computing system to perform a method,wherein directing the wireless interrogation unit includes directing acontrol unit associated with the wireless interrogation unit.

48) The non-transitory computer readable storage medium according to anyone of embodiments 44 to 47, wherein said knee replacement, medicaldevice, or kit is an assembly according to any one of embodiments 1 to20 or 25 to 27.

49) The storage medium according to any one of embodiments 44 to 48wherein said collected sensor data is received on a watch, wrist band,cell phone or glasses.

50) The storage medium according to any one of embodiments 44 to 49wherein said collected sensor data is received within a subject'sresidence or office.

51) The storage medium according to any one of embodiments 44 to 50wherein said collected sensed data is provided to a health careprovider.

52) The storage medium according to any one of embodiments 44 to 51wherein said sensed data is posted to one or more websites.

53) The method according to any one of embodiments 39 to 43, or storagemedium according to any one of embodiments 44 to 52, wherein said datais analyzed. Within certain embodiments the data can be analyzed toassess range of motion of a subject. Within other embodiments, the datacan be analyzed to assess or detect bone erosion, inflammation, surfacewear, and/or deterioration and/or possible breakage or breakage of theknee prosthesis, medical device or kit (or any portion thereof).

54) The method or storage medium according to embodiment 53 wherein saiddata is plotted to enable visualization of change over time.

55) The method or storage medium according to embodiments 53 or 54wherein said data is plotted to provide a three-dimensional image.

56) A method for determining degradation of a knee replacement, medicaldevice or kit, comprising the steps of a) providing to a subject a kneereplacement, medical device or kit according to any one of embodiments 1to 20 or 25 to 27, and b) detecting a change in a sensor, and thusdetermining degradation of the knee replacement, medical device or kit.

57) The method according to embodiment 56 wherein said sensor is capableof detecting one or more physiological and/or locational parameters.

58) The method according to embodiment 56 or 57 wherein said sensordetects contact, fluid flow, pressure and/or temperature.

59) The method according to any one of embodiments 56 to 58 wherein saidsensor detects a location within the subject.

60) The method according to any one of embodiments 56 to 59 wherein saidsensor moves within the body upon degradation of the knee replacement.

61) The method according to any one of embodiments 56 to 60 wherein thestep of detecting is a series of detections over time.

62) A method for determining an infection associated with a kneereplacement, medical device or kit comprising the steps of a) providingto a subject a knee replacement, medical device or kit according to anyone of embodiments 1 to 20 or 25 to 27, wherein said knee replacement,medical device or kit comprises at least one temperature sensor and/ormetabolic sensor, and b) detecting a change in said temperature sensorand/or metabolic sensor, and thus determining the presence of aninfection.

63) The method according to embodiment 62 wherein the step of detectingis a series of detections over time.

64) The method according to embodiments 62 or 63 wherein said change isgreater than a 1% change over the period of one hour.

65) The method according to embodiments 62 to 64 wherein said change isa continually increasing temperature and/or metabolic activity over thecourse of 4 hours.

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications and non-patent publications referred to in thisspecification are incorporated herein by reference, in their entirety.Aspects of the embodiments can be modified, if necessary to employconcepts of the various patents, applications and publications toprovide yet further embodiments.

In general, in the following embodiments, the terms used should not beconstrued to limit the embodiments to the specific embodiments disclosedin the specification and the embodiments, but should be construed toinclude all possible embodiments along with the full scope ofequivalents to which such embodiments are entitled. Accordingly, theembodiments are not limited by the disclosure.

What is claimed is:
 1. A knee replacement prosthesis comprising: atleast one of a tibial component, a patellar prosthesis, and a femoralcomponent; and a plurality of sensors coupled to at least one of thetibial component, patellar prosthesis, and femoral component.
 2. Theknee replacement prosthesis of claim 1 wherein the plurality of sensorsincludes a sensor on the tibial component.
 3. The knee replacementprosthesis of claim 1 wherein the plurality of sensors includes a sensoron the patellar prosthesis.
 4. The knee replacement prosthesis of claim1 wherein the plurality of sensors includes a sensor on the femoralcomponent.
 5. The knee replacement prosthesis according to any one ofclaims 1 to 4 wherein said sensor is selected from the group consistingof accelerometers, pressure sensors, contact sensors, position sensors,chemical microsensors, tissue metabolic sensors, mechanical stresssensors and temperature sensors.
 6. The knee replacement prosthesisaccording to claim 5 wherein said accelerometer detects acceleration,tilt, vibration, shock and or rotation.
 7. The knee replacementprosthesis of claim 1 wherein the plurality of sensors includes contactsensors positioned on the femoral component.
 8. The knee replacementprosthesis of claim 1 wherein the plurality of sensors includes aplurality of contact sensors positioned on the patellar component. 9.The knee replacement prosthesis of claim 1 wherein the plurality ofsensors includes a plurality of contact sensors positioned on the tibialcomponent.
 10. A medical device, comprising a femoral component of aknee replacement prosthesis and a plurality of sensors coupled to saidfemoral component.
 11. A medical device, comprising a patellarprosthesis of a knee replacement prosthesis and a plurality of sensorscoupled to said patellar prosthesis.
 12. A medical device, comprising atibial component of a knee replacement and a plurality of sensorscoupled to said tibial component.
 13. The medical device according toany one of claims 10 to 12, wherein said sensors appear within and/or onthe surface of said medical device.
 14. The medical device according toany one of claims 10 to 13 wherein said sensor is selected from thegroup consisting of accelerometers, pressure sensors, contact sensors,position sensors, chemical microsensors, tissue metabolic sensors,mechanical stress sensors and temperature sensors.
 15. The medicaldevice according to claim 14 wherein said accelerometer detectsacceleration, tilt, vibration, shock and or rotation.
 16. The kneereplacement prosthesis according to any one of claims 1 to 9 or medicaldevice according to any one of claims 10 to 15 further comprising: anelectronic processor positioned upon and/or inside at least one of thetibial component, patellar prosthesis and/or the femoral component thatis electrically coupled to sensors.
 17. The knee replacement prosthesisor medical device of claim 16 wherein the electric coupling is awireless coupling.
 18. The knee replacement prosthesis or medical deviceof claim 17 further including: a memory coupled to the electronicprocessor and positioned upon and/or inside the at least one of tibialcomponent, patellar prosthesis and femoral component.
 19. The kneereplacement prosthesis or medical device according to any one of claims1 to 18 wherein said sensor is a plurality of sensors which arepositioned on or within said knee replacement at a density of greaterthan 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 20 sensors per square centimeter.20. The knee replacement or medical device according to any one ofclaims 1 to 19 wherein said sensor is a plurality of sensors which arepositioned on or within said knee replacement at a density of greaterthan 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 20 sensors per cubic centimeter.21. A method comprising: obtaining contact data from contact sensorspositioned at a plurality of locations between on and/or within a kneereplacement prosthesis or medical devices according to any one of claims1 to 20 of a patient; storing the data in a memory device located on orwithin the knee replacement prosthesis or medical device; andtransferring the data from the memory to a location outside the kneereplacement prosthesis or medical device.
 22. The method according toclaim 22 further including: obtaining strain data from strain sensorspositioned at a plurality of locations on the knee replacementprosthesis or medical device of a patient; storing the strain data in amemory located in said knee replacement prosthesis or medical device;and transferring the strain data from the memory to a memory in locatedoutside the knee replacement prosthesis or medical device.
 23. Themethod according to claim 22 further including: obtaining contact datafrom contact sensors positioned in a knee replacement prosthesis ormedical device according to any one of claims 1 to 19 of a patient;storing the contact data in a memory located in the knee replacementprosthesis or medical device; and transferring the data from the memoryto a memory in a location outside of the knee replacement prosthesis ormedical device.
 24. A method comprising: obtaining acceleration datafrom accelerometers positioned at a plurality of locations on a kneereplacement prosthesis or medical device according to any one of claims1 to 19 located in-situ in the knee of a patient; storing theacceleration data in a memory located in the knee replacement prosthesisor medical device; and transferring the acceleration data from the saidmemory in the knee replacement prosthesis or medical device to a memoryin a location outside the knee replacement prosthesis or medical device.25. A kit comprising the knee replacement prosthesis or medical deviceaccording to any one of claims 1 to 19, further comprising bone cementand/or bone screws comprising one or more sensors.
 26. The kit accordingto claim 25 wherein said one or more sensors are selected from the groupconsisting of accelerometers, pressure sensors, contact sensors,position sensors, chemical microsensors, tissue metabolic sensors,mechanical stress sensors and temperature sensors.
 27. The kit accordingto claim 25 or 26 wherein said sensors appear on said prosthesis ormedical device at a density of greater than 1, 2, 3, 4, 5, 6, 7, 8, 9,10 or 20 sensors per square centimeter.
 28. The knee replacement,medical device, or kit according to any one of claim 1-20 or 25-27wherein the one or more of the sensors are placed randomly within theknee replacement, medical device or kit, and/or at specific locationswithin the knee replacement, medical device or kit.
 29. A method fordetecting and/or recording an event in a subject with a knee replacementor medical device as provided in any one of claims 1 to 28, comprisingthe step of interrogating at a desired point in time the activity of oneor more sensors within the knee replacement or medical device, andrecording said activity.
 30. The method according to claim 29 whereinthe step of interrogating is performed by a subject which has animplanted knee replacement or medical device.
 31. The method accordingto claim 30 wherein said recording is performed on a wearable device.32. The method according to any one of claims 29 to 31, wherein saidrecording is provided to a health care provider.
 33. A method forimaging a knee replacement, medical device or kit according to any oneof claims 1 to 20 or 25 to 27, comprising the steps of (a) detecting thelocation of one or more sensors in a knee replacement, medical device,or kit according to any one of claims 1 to 20 or 25 to 27; and (b)visually displaying the location of said one or more sensors, such thatan image of the knee replacement or medical device is created.
 34. Themethod according to claim 33 wherein the step of detecting occurs overtime.
 35. The method according to claim 34, wherein said visual displayshows changes in the positions of said sensors over time.
 36. The methodaccording to any one of claims 33 to 35 wherein said visual display is athree-dimensional image of said knee replacement or medical device. 37.A method for inserting a knee replacement, medical device or kitaccording to any one of claims 1 to 20 or 25 to 27, comprising the stepsof (a) inserting a medical device according to any one of claims 1 to 20or 25 to 27 into a subject; and (b) imaging the placement of saidmedical device according to the method of any one of claims 33 to 36.38. A method for examining a knee replacement, medical device or kitaccording to any one of claims 1 to 20 or 25 to 27 which has beenpreviously inserted into a patient, comprising the step of imaging theknee replacement or medical device according to the method of any one ofclaims 33 to
 36. 39. A method of monitoring a knee replacement, medicaldevice, or kit within a subject, comprising: transmitting a wirelesselectrical signal from a location outside the body to a location insidethe subject's body; receiving the signal at a sensor positioned on aknee replacement, medical device, or kit according to any one of claims1 to 20 or 25 to 27 located inside the body; powering the sensor usingthe received signal; sensing data at the sensor; and outputting thesensed data from the sensor to a receiving unit located outside of thebody.
 40. The method according to claim 39 wherein said receiving unitis a watch, wrist band, cell phone or glasses.
 41. The method accordingto claim 39 or 40 wherein said receiving unit is located within asubject's residence or office.
 42. The method according to claims anyone of claims 39 to 41 wherein said sensed data is provided to a healthcare provider.
 43. The method according to any one of claims 39 to 42wherein said sensed data is posted to one or more websites.
 44. Anon-transitory computer-readable storage medium whose stored contentsconfigure a computing system to perform a method, the method comprising:identifying a subject, the identified subject having at least onewireless knee replacement, medical device, or kit according to any oneof claims 1 to 20 or 25 to 27, each wireless knee replacement, medicaldevice, or kit having one or more wireless sensors; directing a wirelessinterrogation unit to collect sensor data from at least one of therespective one or more wireless sensors; and receiving the collectedsensor data.
 45. The non-transitory computer-readable storage medium ofclaim 44 whose stored contents configure a computing system to perform amethod, the method further comprising: identifying a plurality ofsubjects, each identified subject having at least one wireless kneereplacement, medical device, or kit, each wireless knee replacement,medical device, or kit having one or more wireless sensors; directing awireless interrogation unit associated with each identified subject tocollect sensor data from at least one of the respective one or morewireless sensors; receiving the collected sensor data; and aggregatingthe collected sensor data.
 46. The non-transitory computer-readablestorage medium of claim 44 whose stored contents configure a computingsystem to perform a method, the method further comprising: removingsensitive subject data from the collected sensor data; and parsing theaggregated data according to a type of sensor.
 47. The non-transitorycomputer-readable storage medium of claim 44 whose stored contentsconfigure a computing system to perform a method, wherein directing thewireless interrogation unit includes directing a control unit associatedwith the wireless interrogation unit.
 48. The non-transitory computerreadable storage medium according to any one of claims 44 to 47, whereinsaid knee replacement, medical device, or kit is an assembly accordingto any one of claims 1 to 20 or 25 to
 27. 49. The storage mediumaccording to any one of claims 44 to 48 wherein said collected sensordata is received on a watch, wrist band, cell phone or glasses.
 50. Thestorage medium according to any one of claims 44 to 49 wherein saidcollected sensor data is received within a subject's residence oroffice.
 51. The storage medium according to any one of claims 44 to 50wherein said collected sensed data is provided to a health careprovider.
 52. The storage medium according to any one of claims 44 to 51wherein said sensed data is posted to one or more websites.
 53. Themethod according to any one of claims 39 to 43, or storage mediumaccording to any one of claims 44 to 52, wherein said data is analyzed.54. The method or storage medium according to claim 53 wherein said datais plotted to enable visualization of change over time.
 55. The methodor storage medium according to claim 53 or 54 wherein said data isplotted to provide a three-dimensional image.
 56. A method fordetermining degradation of a knee replacement, medical device or kit,comprising the steps of a) providing to a subject a knee replacement,medical device or kit according to any one of claims 1 to 20 or 25 to27, and b) detecting a change in a sensor, and thus determiningdegradation of the knee replacement, medical device or kit.
 57. Themethod according to claim 56 wherein said sensor is capable of detectingone or more physiological and/or locational parameters.
 58. The methodaccording to claim 56 or 57 wherein said sensor detects contact, fluidflow, pressure and/or temperature.
 59. The method according to any oneof claims 56 to 58 wherein said sensor detects a location within thesubject.
 60. The method according to any one of claims 56 to 59 whereinsaid sensor moves within the body upon degradation of the kneereplacement.
 61. The method according to any one of claims 56 to 60wherein the step of detecting is a series of detections over time.
 62. Amethod for determining an infection associated with a knee replacement,medical device or kit comprising the steps of a) providing to a subjecta knee replacement, medical device or kit according to any one of claims1 to 20 or 25 to 27, wherein said knee replacement, medical device orkit comprises at least one temperature sensor and/or metabolic sensor,and b) detecting a change in said temperature sensor and/or metabolicsensor, and thus determining the presence of an infection.
 63. Themethod according to claim 62 wherein the step of detecting is a seriesof detections over time.
 64. The method according to claim 62 or 63wherein said change is greater than a 1% change over the period of onehour.
 65. The method according to claims 62 to 64 wherein said change isa continually increasing temperature and/or metabolic activity over thecourse of 4 hours.